How to build homes with virtually no heating (2020) | Hacker News Reader

How to build homes with virtually no heating (2020)

archipro.co.nz

365 pointswhereistimbo326 comments

I've also built a simple and small (99sqm) PassivHaus in Romania, 5 years ago. Everybody, and I mean everybody from family to friends called me nuts, but I've got my payback this winter when the energy prices went trough the roof and I'm just slightly affected.

The house is elevated from the ground on 12 concrete columns so that I can insulate under the foundation beams using glass foam, insulation on walls is 30 cm of EPS graphite, underfloor 45 cm EPS and on the roof, 50 cm and the orientation is full on south. For heating it consumes about 1500-2000 kWh per year (December, January, February and a maybe a small part of March)

What is the big difference between houses built in North America and Europe is that the European houses are built using concrete and masonry which give them a lot of thermal mass which is crucial to this kind of builds.

Have a look here [0], this is the first PassivHaus in my area and is nicely documented. The cost of building a PassivHaus in my country typically goes about 20-25% more than a traditional one.

[0]: http://www.sdac.ro/site/archives/category/passivehouse

It is interesting that you insulate under the house.

One of the more intriguing passive house designs I saw was one where the insulation went down 2-3m into the ground all around the house footprint. This trapped the natural ground heat within that area and fed it upwards into the house. It took about 18 months for the ground to warm up, but once it was there, the ground/house warmed itself with virtually no input.

This was in the UK. Colder climates may vary ofc.

We have an old house from 1988 located in Norway. Walking on the non-insulated wooden floor is very unpleasant. We will refurbish, and insulate under the floor, but it will not be anything near a passive house because of other construction shortcomings

well try non-insulated tiles here in Spain haha. I don't know why houses are built to such a low standard in Spain. Even the UK had better quality constructions when I was there, and that says a lot (single glazed windows, poor insulation, weak plumbing)

no harsh climate overall so much less insulation is needed?

Mainland Spain falls into the single digits at night at winter so definitely would need insulation, because there is also no central heating. People resort to heating with their aircons and portable heaters. I'm sad because I expected better infrastructure from 45% income tax at the highest bracket.

I come from Poland (sub-zero in winter; can be anywhere from -20C to +10C but typically 0-5C), but the winter I lived on the Spanish eastern coast was the coldest in my life: thin walls and windows, stone floor, no heating apart from little portable heaters, 5 degrees and rain outside.

Now I live in French southern coast, the buildings are slightly better but still poor. In my place even with all heaters I have on max, I'm nowhere near as comfortable as in properly built and heated apartments in my home place (actually when visiting friends in Poland in winter I'm almost overheating!).

Basically half of the year it's quite uncomfortable to stay at home for prolonged time: for ~4 months a year at winter; then again for ~2-3 months at summer (+26C at home with blinds down unless you put aircon on max for hours). Kinda suboptimal for WFH to be honest :)

I have an acquaintance in Madrid. Visiting her, I never know what to prepare for.

An Easter visit was miserable, because the condo building did not even have central heating. With night temperatures around 5 degree Celsius, I could barely sleep.

Then comes the summer and 40+ Celsius is at least as unbearable...

Spanish construction standards are pretty ascetic.

Portugal manage to be even worse. You’ll be stood there in someone’s kitchen wearing a coat and gloves, watching your breath condense, and they’ll be like “oh but we don’t get cold winters like you do in the northern countries”. That’s the rationale. The reason is actually more likely financial.

Exactly. Talking about thermal mass!

There’s also the movement of underground houses. They use the ground for cooling in summer and for insulation in winter. Also it apparently makes for great noise reduction, in spite of having lots of windows, light and views.

See the book “Recovering America: A More Gentle Way to Build”.

Underground houses can be a nightmare dealing with water infiltration, codes and the power of soil.

Really interesting. I've read about also "foundation insulation skirt" that allows you to create a warmer earth mass under the house.

To be honest this was the biggest "complaint" that others had in regards of how a built the house, the general knowledge says that the earth is warm and you don't need to insulate against it... but the earth is maybe 5-10 degree, of course warmer than outside -5..-10 but still a lot colder than what we want inside the house, 20,21 degree C.

That depends on how deep you dig, but of course going deep enough has a cost that may be far greater than the kind of insulation you used.

The 20-25% of increase in cost is a good proxi (from my personal experience I would have said 25-30%), but, from an economical standpoint it should be compared with savings over time (in the same region).

To give you an example in Italy, last time I calculated it, this 25-30% increase of costs corresponds - loosely - to the costs of heating for 20 years or so (bar the crazy increases in prices of energy that just happened), so it becomes more a "philosophical" choice than anything else to go for passive or almost passive.

5% return per year (or more in case of price changes or regulations forcing you to change heating source) does not seem that "philosophical".

I don't understand fully your way of reasoning.

A normal house costs - say - 200,000 "units" (dollars, euro, whatever).

Making it "energy saving" costs an additional 60,000 units.

In 20 years time you will be spending 60,000 units (3,000 per year) less for energy costs (and here we are assuming that ventilation and heating/cooling machines in the "better" house have the same maintenance costs than the ones in "normal" house, whilst usually, since they are more complex systems they tend to be more expensive).

You essentially have a "break even" point 20 years in the future, from there onwards you start saving money.

First thing, you need, now, 260,000 units instead of 200,000 (and not all people may be able to afford this).

Then, if, for whatever reasons, you don't use the house at all times in these 20 years, or you need to sell it before that time you are unlikely to fully get the savings.

Additionally, in less than 20 years time it is possible that someone comes out with a mega-para-hyper-ultra climatization device that makes yearly energy costs go down by (say) 90%.

So, if you want to do the "right thing" from a climate/energy savings point of view, by any means choose to invest in a passive house, but it remains essentially a "philosophical" decision, not an economical one.

Not only "philosophical", better insulated houses are also more comfortable.

Sure, but not all houses are built for "you" to live in perpetually.

You build a house according to the minimal requirements of your local codes/norms.

If you next year go to another city you may either sell the house or rent it (at average market value).

You build a "passive house".

If you next year go to another city you may either sell the house or rent it.

Do you believe you can easily get 30% more rent or sale price because it is passive?

It’s rather pointless to go through the effort of building a house if you don’t expect to live in it for very long. So, the minimum standards should only be relevant to people building homes for sale.

As to insulation, it’s very cheap to add some form of solar heating outside of the arctic but cooling always takes energy.

What you expect may be different from what will eventually happen, and since the vast majority of houses are actually built by people that intend to sell them (builders), those make the market price, and - at least now - a passive house valued 30% more than average market is not easy to sell or rent, maybe this will change, maybe not.

You can very much rent a passive house for significantly more by including heating and cooling costs into the rental price. People can’t see what your heating bills are but they can compare with other properties that include heating.

Actual price differences at time of sale should be nowhere close to 30% not only because that’s an insane difference in construction costs but also because land isn’t free. A 200k house on 200k of land vs a 260k house on 200k of land isn’t a 30% difference in final price.

Still it remains 60K difference, or 20 years at 3K.

Assuming it is actually 60k, where in reality insulation is cheap. Having giant windows is useful for passive heat gain, but their mostly installed for aesthetics not practicality. Which means aesthetics are also increasing home values.

In terms of pure economics an extra 15k in insulation and 15k for a solar hot water system gets you further at much lower costs by actually providing hot water for showers not just lowering heating bills.

I think you are downsizing the project, from investing 60K to save 3K/year to investing 30K to save 1.5K/year.

No, I am saying you would save that much money more cheaply via other methods.

Sure, saving 3k/year on heating costs for a single family home is extremely high. An average 1,800sf house in Massachusetts on $1.87/therm natural gas is only projected at $1,243 / year in heating bills for 2021/2022. That said you can always build a larger house, so saving 3k/year isn’t impossible it’s just much easier when you include better methods to collect sunlight than covering a side of your house in giant windows which have low R factors because their giant windows.

PS: Insulation alone can only make so much difference. In other words you might save 1000$/year going from R10 to R20, but then going from R20 to R30 doesn’t also save you another 1,000$. Very quickly you’re better off collecting energy rather than reducing heat loss.

If you step back a bit, it makes sense for society to push for the construction techniques that minimize the lifetime cost of the building. Here, buildings typically last for much longer than 20 years.

And then there's the whole thing where energy costs may not be fully priced into the use.

Sure, but then that is a "political" decision at government level, not your "free" choice.

It is clear that the (good) trend is towards mandating "better" insulation (and thus less energy consumption) but it is not like a government can say "ok, starting tomorrow all new houses must be passive", as that translates to "ok, starting from tomorrow price of all new houses will increase by 30%".

They are introducing - little by little - minimal requirements, and introducing in parallel some (BTW badly implemented at least here in Italy) economic incentives to better existing houses but it will take many years before they can impose "only passive" houses, and in any case, "new houses" are such a trifling percentage of existing buildings that they won't make a dent in the overall energy consumption, it is much more effective, given the amount to slightly better the much larger amount of existing buildings.

Also it is not as easy as it seems, for the last 10-20 years a number of houses have been built in the (at the time) energy classes A-B-C without mechanical ventilation/heat exchangers, with - let's call them "not fully tested" - construction methods and now that they are aging they show the problems emerging (humidity/mould, maintenance of windows, decay of insulation packets/facades, etc.), as often happens with new technologies.

>construction techniques that minimize the lifetime cost of the building. Here, buildings typically last for much longer than 20 years. And then there's the whole thing where energy costs may not be fully priced into the use.

It goes both ways. Investing in capex has to be balanced against potential capex and opex market changes, not just today's market.

Unless that 0% rate gets passed onto you, there's a fairly rigid payback wall at 30 yrs where no amount of investment is going to make financial sense. (It's why despite loan terms growing for everything else, mortgages are still capped at 30 yrs.

What happens when the market is flooded with cheap renewable electricity, as is promised? Suddenly your payback period is extended beyond what makes sense.

Or advances in technology result in a cheaper, better insulation material?

And then there's the potential external costs of not just energy, but material and construction. It wasn't that long ago that asbestos singles covered nearly every new house because of its fire resistance and insulating properties.

The cost there also seemed to pay for itself, until we discovered the true cost of asbestos mitigation and removal.

"You essentially have a "break even" point 20 years in the future, from there onwards you start saving money."

That's exactly how a 5% roi investment works. There is nothing unusual here.

"in less than 20 years time it is possible that someone comes out with a mega-para-hyper-ultra climatization device that makes yearly energy costs go down by (say) 90%"

And it's possible second coming of Christ will happen, or an asteroid will fall, and you'd be better off soending money on hookers and cocaine.

A plan that relies on some unrelated events to solve your problems is not a plan. Why bother planning at all then?

This was a problem that hit the first solar adopters. Their break-even was so far in the future because the technology really ramped up later. Of course, one could argue perhaps that wouldn't have happened without the adoption. And perhaps argue against that again that it was gov subsidies that really pushed solar to primetime.

>That's exactly how a 5% roi investment works.

Not exactly, in a 20 years 5% roi investment you normally get your invested capital (admittedly reduced in real terms by inflation) back.

In this case a the end of the 20 years you have something that has degraded and that probably needs replacing (talking of ventilation systems or solar panels) and/or needs repairs.

I find it more like a 5 year lease for a car vs buying it cash.

did you include heating costs rate of change growing? (i.e. prices rise more % yoy with each year?)

Insulation under the home, and skirted around it. You may be thinking of a Frost Protected Shallow Foundation[1]. A nice alternative to excavating in order to get below the frost line. I dream of doing this as part of a self built small passive house project.

[1]: https://www.greenbuildingsolutions.org/blog/frost-protected-...

ICF construction where the foundation form is Styrofoam Lego like blocks that concrete is poured into achieves this shallow and in full basement hooded. A lot more homes in Canada use this approach now.

> It is interesting that you insulate under the house.

Isn't that pretty normal, I mean maybe not three meters down, but modern foundations are required to be isolated in many places. The legal requirement in Denmark is at least 300mm of isolation under the house.

And that's not a new thing either.

In my 1970's house we have 150mm insulation under the house from the original build, 150mm in the walls and 200mm on the roof.

We added another part to the house a few years ago, and that was 300mm insulation in floor/walls/roof. Since the walls are made of brick with a depth of 7cm, it means the walls are 7+7+30= 44cm thick (plus some "slack")

Even my 1980's summerhouse has 100mm insulation in floor/walls/roof.

That depends of the the place where you live. In middle to the south of Spain, the floor of houses are normally made of marble (or other ceramic material) slabs on top of a little layer of some glue cement, on top of the armoured concrete slab foundation, but on the north is a lot common to have wooden floors with air chamber of a similar size.

It is indeed normal. I mentioned it by way of an intro to the unusual alternative I saw.

How would that work? Average temperature in the UK is about 15 C. If your house is at 24 C, this would mean you are constantly leaking heat into the ground from the bottom...

I guess one can consider the cube of earth an insulator, it's got a lousy insulation value per meter but it makes it up in thickness.

Don't think 15C is correct - looks more like 8.5C to 11C in England and 7C to 9C in Scotland.

http://projectbritain.com/weather/average.htm

You can look up ground temperature for your location here - https://weatherdownloader.oikolab.com/downloader.

Layer 4 is between 1m to 3m depth beneath the surface.

Apologies, I didn't appreciate you meant average temperature underground - that is definitely much warmer. We have a ventilation shaft for an old limestone mine near our house and on a cold day the warm air rising from it is very noticeable.

I wasn't the commenter so no worries about apologies... just wanted to point out where you can find this information. :)

Sorry, I was wrong indeed, thanks for the correction

> It is interesting that you insulate under the house.

Near our place in the countryside, required foundation depth is 1.4m to protect from frost heave. Use an insulated slab and that requirement goes away. The insulation keeps the heat in the ground. It protects the ground under the house from freezing.

Nobody cares about regulations here, but they do about getting proper foundations...

> The insulation keeps the heat in the ground. It protects the ground under the house from freezing.

If it is preventing the ground under the house from freezing, then it is supplying heat to that ground. That's a energy-negative process - some of the heat you generate is used to maintain the warmth of the ground.

Some of your heat is always going into the ground. The insulation prevents it from dissipating into the environment.

Au contraire, my dear Watson.

Without under-slab insulation, the heat emanating from the ground below the house escapes very quickly. This heat we don't generate. It occurs naturally. This is about using the naturally escaping heat to keep the ground under the house from freezing, about raising the frost depth.

This technique is especially interesting for holiday homes not permanently heated in northern climates. It's fairly standard in Scandinavia, up and coming in the Baltics, but less known in the US.

In the US, it's usually called FPFS or frost protected shallow foundations. [0]

[0] https://www.ncei.noaa.gov/products/land-based-station/frost-...

> It is interesting that you insulate under the house.

This is part of the building code in many areas: do a search for [under] "slab insulation".

* https://www.buildingscience.com/documents/information-sheets...

* https://www.finehomebuilding.com/project-guides/insulation/i...

It should be at least R-10 (RSI 1.8):

* https://www.youtube.com/watch?v=O2dNp9bicSk

* https://www.youtube.com/watch?v=XKp0wRzvR-g

> It is interesting that you insulate under the house.

I think anyone who's gone camping will appreciate the need for insulation between the ground and whatever you're trying to keep warm - a good sleeping pad is crucial for keeping warm.

Do you have a link on this? I’d love to read more about this.

We’ve just built a 45m2 log cabin to passive standards here in Portugal - heavily insulated in walls, floor, roof, lifted off the ground on concrete columns, double glazed, only heat source is a 2.5kw log stove. Everyone here (who all live in uninsulated concrete houses heated by open fireplaces) said we will freeze in the winter, roast in the summer. We situated the house on a north facing slope, to minimise sun exposure in the summer. Means little direct light in the winter, but we think (have yet to experience a summer in it) the balance will be good.

As I write this, the stove is out, having burned out overnight, it’s -11 outside, and 25 inside. We are getting through a ridiculously tiny volume of firewood compared to when we were living in a more traditional house for here - less than ⅛ the volume.

Insulation works. It’s also cheap. I don’t understand why people would build new structures without it.

> Insulation works. It’s also cheap. I don’t understand why people would build new structures without it.

People are a bit sceptical about many insulation forms... plastic-based stuff is either a fire hazard (see Grenfell Tower) or extremely toxic waste (if it has been treated with fire suppressants), asbestos is completely banned for good reasons, and rock/glass wool can also spread nasty ultra-fine dust.

We’ve purely used rockwool. It’s enclosed within a semipermeable membrane, so no possibility of dust escaping.

It would be very interesting to learn more about this build. Was it something pre-fabricated (I've seen "kit" log homes advertised) or something completely custom?

Pre-fab, although loosely so - about 1000 me-hours to make it into a functional home. I unfortunately can’t recommend the outfit I bought it from, as they screwed up and shipped only part of the order, sent me defective parts (bad and/or incorrectly machined timbers), and had the worst post-sales service I’ve encountered in anything - but there are plenty of companies out there that make decent kit cabins.

What do you do for fresh air? We have a very well insulated cabin heated by fire, but find the CO2 builds up, particularly overnight with no doors opening, and if we aren’t very quick to close the fire once it gets going, PM2.5 can jump quickly.

We sleep with the window open in the bedroom, and I air the place each morning. Also, it’s almost too well insulated, as it’s easy to accidentally make it 30C in here while it’s -9 outside - so more often than not we have a window cracked open for some air whilst sat in in the evenings. Our PM2.5 is often a silly number, same reason. I’m considering getting an air purifier, but to be honest, given all the crap I’ve inhaled whilst building the place, and given that I smoke anyway, it’s low on my list.

People doesn't give the massive importance the isolation has. Some years ago we remodelled our home and added XPS (Extruded Polystyrene) to insulate the roof of the house. After that we use the AC only three or four days in the year, and before that we had to use it at least a complete summer month. That house is in the south-interior of Spain, so heat is no joke here.

If somebody are constructing or remodelling any house I recommend it to add any insulation they can in any shape, in less than five years you'll recover what you spend, and if you add PV panels for electricity or a thermosiphonic system to heat water, you'll recover the investment in about 10 years, with a healthy amount of available health in the devices to continue saving money with a proper maintenance.

> That house is in the south-interior of Spain, so heat is no joke here.

I looked up a few areas (Ciudad Real) to see what you meant by heat, but it seems quite similar to a good portion of the northern USA. This makes sense, I suppose, given the similar latitude.

Insulation is so, so important. I work out of my garage currently and Texas winters get reasonably chilly and of course summers are hot. I'm lucky enough that my garage is actually under a room in my house such that it's insulated (as you imply, roof insulation is one of the most important places to insulate). Even simply adding padded insulation and trim to the exterior door and garage door made it viable enough to stay cool in the summer with zero extra cooling and warm in the winter with a small infrared heater.

What people definitely don't give enough importance is CO2 buildup as well. The more isolated a place is, and smaller, the more environment friendly it is BUT the more likely it is to build up CO2, which leads to headaches.

I installed a CO2 meter both at my current home, and at my parent's home for when I go back for Christmas. In my home, it's a fairly big open place so it takes ~2 days of closed windows (0-3C outside) to reach 2000PPM (recommended under 1000, above 2000 starts affecting you, 5000 is the legal limit[1]). However, at my family home where I grew up it's a tiny room and it reaches 3000-4000 just by sleeping there with the window and door closed. So the headaches of "visiting family" might in big part be explained by this.

PS, incidentally in Spain!

[1] https://www.kane.co.uk/knowledge-centre/what-are-safe-levels...

that is why you need a Heat Exchanger

I suspect I'm experiencing some of this in a small home with poor circulation. Any suggestions for inexpensive room monitoring sensors?

I just bought one on my local Amazon version by searching "CO2 meter". While true numerical accuracy is "who knows", on rest/full ventilation it shows 400PPM and blowing at it (even gently) shows the CO2 increases drastically, as expected, so I'm happy with it.

These are starting to catch on, as someone else said Heat Exchanger, but that's a more general concept and this is the thing you'd actually want https://en.wikipedia.org/wiki/Energy_recovery_ventilation

What about windows? I find buildings with few or small windows to be unmanageably dreary, but the math works out that no matter how insulated you make the walls if you have a good amount of glazing on the walls the effective R value drops quite low.

You always can use isolated glass panels and wood or plastic frames to prevent that: https://www.energy.gov/energysaver/window-types-and-technolo...

I personally have gas filled glass panels and are pretty good at that, but I wish I had also those that have an IR filter coating that prevent IR heat from entering and from exiting the house. That was a lot more expensive when I installed mine.

It seems like historically people underestimated the insulation value of polyurethane because apparently it doesn't necessarily do well on the conventional R-value score.

Apparently a solid inch of sprayed polyurethane can provide 90% insulation, and 2 inches gets you to 99% insulation.

https://www.monolithic.org/blogs/presidents-sphere/r-value-f...

> What is the big difference between houses built in North America and Europe is that the European houses are built using concrete and masonry which give them a lot of thermal mass which is crucial to this kind of builds.

Here's a 500 sq. m. (5000 sq. ft.) house built with heating equipment that uses 1800W (the equivalent of a hair drier):

* https://www.youtube.com/watch?v=_vul4vMFdkA

The same person building his own personal home up to Passive House standards:

* https://www.youtube.com/watch?v=mBOvflXoWlw

You do not need concrete† and masonry to make homes efficient. Switching from using 2x4s @16" off centre (OC), to 2x6 @24" OC ("advanced framing") would allow for less wood use, less thermal bridging, and more cavity space for insulation.

† It should be noted that concrete creates a lot of CO2 emissions, as does baking bricks. Growing wood on the other hand is a way to sequester carbon.

I agree, you do not need concrete and brick but you also need to take into account the local traditions. For ex. building a wood house (framing or CLT) would have cost much more than concrete and bricks and was also much more prone to errors because of the builders lack of experience, at least in my area and country.

Recently in Romania it really took of building houses using CLT (cross-laminated-timber) but it costs so much more than a regular brick and mortar house that few people afford it.

When -15 outside and 20 degrees inside, my house requires 2000W to keep the balance. This kind of simulations are done using PHPP package from PassivHaus Institut.

L.E. What I wanted to point out, thermal mass can have a huge impact on the house energy footprint.. to give you an example, today and tomorrow will be sunny days and this will drive my interior temp to about 23-24 degrees, this heat will heat-up the masonry and slabs and then give me back the heat in the next days when there will be no sun.

Wood is fairly inexpensive in North America because there are still many forests (especially in Canada).

There is nothing "inherently better" with one material over another for most applications. A good structure mostly depends on proper drainage and cladding to protect against UV rays and bulk water (precipitation), good air tightness (with mechanical ventilation for filtered, tempered fresh air), and high insulation.

* https://www.buildingscience.com/documents/insights/bsi-001-t...

Modern codes have moved back to 2x4, then they put continuous foam on the outside of that to make the total the width of a.2x6 wall. Wood is not a great insulator and you have to have some

> Modern codes have moved back to 2x4, then they put continuous foam on the outside

Codes do allow for only external insulation, but it it also possible to have some exterior "continuous insulation" with the remainder being in the wall cavity.

The thicker the exterior insulation, the trickier it can be to attach it to the wall and then also have mechanical fasteners for your external cladding.

* https://www.buildingscience.com/documents/insights/bsi-001-t...

* https://www.buildingscience.com/documents/building-science-i...

However, AIUI, using 2x6s reduces the number of studs needed and so would generally reduce the cost on average from both a material and labour perspective (even if 2x6s are slightly higher each).

* https://www.buildingscience.com/documents/insights/bsi-030-a...

* https://buildability.ca/wp-content/uploads/2017/05/M400-Adva...

* https://www.energystar.gov/ia/home_improvement/home_solution...

* https://www.protradecraft.com/article/advanced-framing-dos-a...

And it's not like it's a new technique: it's been around for (at least) forty years.

I should have said modern building and not codes. there are a lot of ways to satisfy good codes, 2x4 tends to be cheapest for single family houses, but others are not far behind and may be worth it in the long run. Consult a proper engineer if you are building a house of course.

Moving insulation outside the frame also helps reduce the effect of thermal bridging although with timber that's not so important as it is with steel.

High thermal mass is definitely more energy efficient in the summer, when you can "store the cold" from the night into the next day.

> small (99sqm)

Is that correct? 99 is not small at all.

Small in comparison with a typical single family homes that goes >150 sqm in my area. I completely agree with you, 99 sqm is more than enough for a 4 people family.

it depends on how you can use the space. 4 people can mean three bedrooms. in some parts of asia the average 3-bedroom flat is 150m². a few years ago i did a search in a european city and likewise was unable to find 3-bedroom apartments with less than 120m². 4 was 150m² minimum.

the problem is huge living rooms that can't be divided up and repurposed to make living space for more people.

work from home doesn't need a lot of space, but with young kids i absolutely need a lockable room. my current office room is 5m². plenty of space. but finding an apartment with that kind of room is rare.

> I did a search in a european city and likewise was unable to find 3-bedroom apartments with less than 120m². 4 was 150m² minimum.

You simply chose the wrong European city :) Try Dublin, the city of 70sqm 3 bed apartments (in fairness, these aren't allowed under current planning regs, but there are quite a lot of old ones).

The average size of homes in the UK is under 80 m2. See https://shrinkthatfootprint.com/how-big-is-a-house

A friend of mine, who is an architect, told me the technology is ripe to build houses that produce even more energy than they consume, but people simply don't want to live in them.

The article talks about "using the best windows", the problem my friend saw in many of such houses was simply that the dwellers would either open the windows too often, losing all the heat, or feel miserable because they weren't allowed to open the windows. A pure psychological effect of course, even with the best ventilation people still had the urge to open a window and felt bad if they couldn't.

I recently lived in a house with no external ventilation in one big room. Huuuge windows looking out onto a huge backyard full of trees and flowers. Yeah I missed being able to open the window and hear the birds. But then when lawnmowers started buzzing and dogs started barking, and later when winter hit, I was quite glad for the peace and quiet and no need to open them!

I never open my windows unless I'm trying to air out something.

how do you ventilate without losing all the heat?

Recuperator ventilation, presumably?

Heat recovery ventilation [1] can bring in fresh air and output old air while recovering the vast majority of the heat.

[1] https://en.wikipedia.org/wiki/Heat_recovery_ventilation

These are only compatible with forced air systems, correct? I.e. using in-floor radiant heat would require an entirely separate ventilation system with heat recovery?

Correct.

https://www.energy.gov/energysaver/whole-house-ventilation

Energy recovery ventilation systems gives a good description

> the technology is ripe to build houses that produce even more energy than they consume, but people simply don't want to live in them

It's called solar. Unless the house has a small footprint most can fit enough solar panels to more than cover their energy use.

> A pure psychological effect of course, even with the best ventilation people still had the urge to open a window and felt bad if they couldn't.

I wouldn't want to live in a house where I couldn't open the windows all the way. Near-perfect energy efficiency is something to strive for but there is something to be said for being able to open the window and get a nice breeze blowing through the house. Even if it isn't the most energy efficient it's okay with me.

> A pure psychological effect of course, even with the best ventilation people still had the urge to open a window and felt bad if they couldn't.

Even if it isn't the most energy efficient it's okay with me. I mean if we really wanted to get good energy efficiency we'd just remove all the windows completely. But we don't because we design building for the enjoyment of humans, not just for energy efficiency.

So with home solar panels and storage getting cheaper and cheaper and better and better, where is the optimization point of investing in better insulation vs just buying more solar panels?

Especially if the solar panels may produce profit on sunny mild days about 40-50% of the year if there is reverse metering and the like?

Insulation beats solar panels. It’s not only much cheaper to get, but also to maintain.

The body heat of a family of 4 is enough to heat a well insulated house.

Solar panels are there to supply electricity for use. The last step of passive houses are zero-energy houses, which means that they don’t get electricity from the grid.

Salut! Could you please share more info / photos / tips, besides the sdac.ro link? How high is the elevation? What kind of heating do you use? How do you refresh the air? (opening the windows or heat recovery system) Thanks

While this is at the extreme end of the spectrum, there is a much easier way to save lots of energy: just build modern well-insulated homes.

I lived in California and I was appalled at the monstrous energy waste: houses are generally made pretty much from cardboard. You need to cool them in summertime and heat them in wintertime, and the energy expenditure is enormous.

I now live in Poland and have recently built small homes that are similar in structure to the ones in CA: wooden frame, drywall inside. But the ones here have walls that are 25cm thick because of insulation (mineral wool) and use advanced modern membranes as well. Together, these things do wonders, and maintaining warmth in wintertime using a heat pump (AC) is easy and doesn't cost an arm and a leg.

In other words, you can get 80% of the benefits with 20% of the effort — just design thicker walls with insulation and use modern materials.

Don't forget to mention that insulating roof is just as important. Otherwise, heat will happily escape over your head.

Yes, I wasn't stating the obvious: you need to insulate the floor and roof as well. For example, reinforced concrete foundation slabs are usually placed over XPS foam boards here. There are many ways to do this, my point was that you don't have to go to extremes to get impressive benefits of modern insulation.

"About the only part of a Californian house you can't put your foot through is the front door." 'The Big Sleep', Raymond Chandler (1939).

Good to see nothing's changed!

Oh, this is so very true! In addition, said front door is protected by a flimsy deadbolt that sits in a dinky thin door frame. The whole thing breaks and opens with a kick and offers symbolic, rather than practical protection.

Of course nothing has changed, he’s talking about the exact same housing stock.

Echoing the sentiment, it cost significantly more for me to heat a studio to 65F in CA than to get a 2/1 up to 72F in ND (or rather, to maintain those temperatures).

Both units had electric baseboard heat and were top floor apartments, but the CA unit didn't have double pane windows, had enormous gaps at the doors and windows, and for all intents and purposes didn't have any insulation. If it was warmer than 0F or so outside the ND unit would have more than enough heat just from cooking. If it was colder than 50F or so the CA unit needed the heaters to actually be on.

I even prefer this to a complete passive house. To be honest I don't like the air from ventilation, although that probably depends on the system.

>I lived in California and I was appalled at the monstrous energy waste: houses are generally made pretty much from cardboard. You need to cool them in summertime and heat them in wintertime,

This is the legacy of historical low energy prices coupled with a historically mild climate.

Now, both of those things are changing. Energy prices are rising because of global warming accelerated risks, and simultaneously the climate is getting hotter and dryer.

The result is that it can start making sense to build to a higher standard like passive house in CA - I just did and my HVAC energy usage dropped 75% and is now more comfortable.

However, there needs to be better code enforcement - i.e. air leakage for new homes should be closer to 2.0 ACH50, not the totally unenforced 5.0 ACH50 on the books today - and also better education of buyers so they can start demanding better built and more efficient homes.

Coming from a decidedly unsexy post-industrial Midwestern city, I was very surprised to learn that for all the wealth and splendor of California, most of the buildings here seem horribly impoverished.

People fail to appreciate how much leveraged financing affects the design of houses. If you pay 100% for a house and you decide to build something only you appreciate using 10% of your budget, you will lose 10% of your investment when selling the house. If you put down 20% and have the bank finance 80%, then the same decision will wipe out 50% of your investment. This means for financed houses, "resale value" becomes the preeminent decision affecting the design of a house.

In Economics, this is known as a "Keynesian Beauty Contest" [1] where your job is to predict what everyone else predicts will be the most popular option and Keynesian Beauty Contests can get weird.

eg: It's quite possible that you might personally hate granite countertops but still feel the need to put a granite countertop in your home because you believe it will help the resale value of your home. It's quite possible for everyone in a community to all hate granite countertops but for everyone to still put granite countertops in their home because they believe everyone else loves granite countertops. It's quite possible for everyone in a community to hate granite countertops and to know that everyone else hates granite countertops and still make the economically rational decision to put a granite countertop in their house to help with the resale value.

A lot of "economically irrational" housing decisions are driven by this core transformation via Mortgage Backed Securities of a house from a consumption based purchase of a place to enjoy living into an investment asset that dominates most people's finances.

It's only in houses built for the independently wealthy that don't really care about the future resale value of their houses that a lot of the good building science expertise still lies. That's why, paradoxically, in countries much poorer than the US/UK/Aus/NZ, you see much better building quality because their finance systems are also less developed.

[1] https://en.wikipedia.org/wiki/Keynesian_beauty_contest

>That's why, paradoxically, in countries much poorer than the US/UK/Aus/NZ, you see much better building quality because their finance systems are also less developed.

source? China isn't well known for their well built buildings for example.

I can't give you hard stats, but in Hungary in the 80s (i.e. socialist times) people were building their own houses in the villages (i.e. with the help from extended family only hiring tradesman when you don't have that trade in family) so there was little reason to cut corners. It also avoided the cookie cutter look of American suburbs. These are brick houses, so they're quite sturdy, and could be modernized by adding external insulation. Most of these houses were built with double glazed windows to begin with, so I was pretty surprised that in Britain or Spain it isn't default.

I'm in the middle of building a PassivHaus. The building itself is mostly done and we're working on the interior. There are still a few gaps that haven't been plugged and the heat exchangers have not yet been installed. I'm above 800m elevation, snowstorms every weekend. It's cold here. My house also actually faces West instead of South, so I'm not getting much heat from the sun. This was a surprise to use because the previous house on the same site had the same orientation and was scorching during the evenings, it's amazing what a pair of Low-E triple paned windows can do.

Despite all that, the builders manage to work inside the building with a single kerosene stove[0]. And the building stays comfortable for several hours even after the stove has been turned off.

[0]: https://nimmi.jp/kurashi-stove/

Sounds great. Do you have a blog or anything online about your project?

Unfortunately no.

I'm looking into making a house sustainable right now and the windows are actually a point of contention. One side thinks super-high insulated (triple pane) windows are a waste of money, the other swears by them. Assuming the frame doesn't leak, does triple really make that much of a difference?

This depends on your house - heat tends to leak out through the lowest path of resistance so if you have a well-insulated house with leaky window, it would certainly be the case but without considering what the rest of the house is like, it would be impossible to tell how much they would help.

Heat leaks out through all path of resistance not just the lowest. (The lowest might dominate though if it is orders of magnitude lower than the second lowest)

For us it did. Estimated 2 degree Celsius on the inside during winter already make a big difference in comfort and how you will use the space in front of the windows.

Windows, walls, ceilings and so on have to match of course, our house is overall well insulated.

Depends on your climate and the heat differential between inside and outside. Triple glazing is effectively double the R-value of double glazing, so in a cold climate yeah..

Get yourself a FLIR (the phone attached ones are not that expensive) and check for yourself. It is a great tool.

As others have said, solutions depend on your climate, and especially on whether you principally have heating or cooling loads.

For cold climates, designers such as Thorstein Chlupp (Rienna LLC, in Fairbanks, AK) rely on triple-paned high emissivity windows for solar gain, and external thermal shutters at night to reduce radiative loss.

For warm climates, you'll want low emissivity glazing, as well as awnings or landscaping which block direct summer sun while admitting light. For winter time, you can probably get by with internal thermal curtains in winter, though an external storm glazing or shutter may also be helpful.

Having windows face the equator (that is, south-facing in the northern hemisphere, north-facing south of the equator) will increase light and decrease heat loss. Glazing on the pole-side of your home is generally reduced, and in sufficiently cold climates, eliminated.

More than you'd ever want to know (2h26m video) here:

https://yewtu.be/watch?v=Xen_VWyDezY

They can be a dream in terms of noise blocking as well.

Yes. Makes measurable difference. Especially big picture windows. Other things to consider: is the type of glass. In places like Arizona you may not want sunlight to get through, but further north, the sun can provide a great deal of heat. So you want transmissivity. To stop that in the summer, you have a overhang roof, far enough out, to block sun in summer but not winter. Also, be smart installing the window, to prevent leakage around the frame, lots of good tricks there. For example- Avoid tightness of frame.

yes, it's like wearing a sweater vs. wearing two sweaters

You must also be careful on how you mount the windows. Have a look at the german standard called "RAL montage" to see that you need an inner and outer membrane and then have a look on where to mount the window inside the wall.. the best solution is to mount it outside the wall in the insulation, the second best solution is to align it at the face of the wall.

Windows have a U or R value like insulation, so you can use that to compare.

We are currently building a house and the triple glazed windows we chose have a U value of 0.9. The same manufacturer also makes double glazed windows which have a U value of 1.3.

Generaly speaking, yes, BUT the design needs to be taken into account.

A window (good as it might be) is "worse" than walls (besides being much more costly), the modern design trends are for extremely huge windows, that (whilst they give much more light, which expecially in northern climates is a wanted feature) are a problem, from a thermal viewpoint.

The typical size of windows in "normal" houses varies (depending on countries) like 1/8 to 1/12 of area of the floor of the room they are in, modern designs can be often 1/5 or 1/6, it is clear that the less amount of window surface you have the less relevant are its characteristics, and you have to consider also the effect of shutters or similar.

In the house I'm living in, which was built in a transition point between making sure houses don't leak and the realization that you then need active ventilation, I have the problem that the windows are not insulating enough, so I end up with water condense on the inside when it's freezing outside. If you are going to replace the windows, I would definitely buy triple-paned, unless you only have a small temperature difference.

they are worth it in cold climates if you use fixed or very fancy casement windows with maintained seals. Double-hung will just leak around frames and sides.

Also ensure you use a good brand which will be around when you need a replacement and hope to get an actual match.

I’ve not had a chance to test it in summer yet but it’s still cold to the touch even in the evening sun so I guess that’s a good sign?

I went with Low E specifically because I’d rather be cold than hot and wanted to block out the scorch from the evening sun.

How is the ventilation and air quality? I work in a passive house in and we're experiencing significant issues with the indoor air quality when the building HVAC turns low.

I wouldn’t know, they aren’t installed yet. Japan doesn’t really do central heating or ventilation so I’ve got 4 smaller air exchangers all over the house and they’re supposed to work together somehow?

Is a stove like that not really dangerous in an air-tight house? Where do the fumes go?

Most air-tight houses have an integrated MVHR (mechanical ventilation with heat recovery) system, which is kind of the inverse of an HVAC setup. There's a constant small air current being moved through the house, and when it exhausts to the outside world a heat-exchanger captures as much heat as possible from the exiting air and uses it to heat the entering air. Airtightness means you can control where the air enters and exits, which means this trick is possible.

All that being said, I'd expect a permanently-installed stove to have a flue (which results in the stove technically being a leak, but that's solvable). I assume the kerosene stove mentioned above is in use while the house is incomplete, so not yet airtight.

Yeah, like fish said it’s not airtight yet so probably not that big of a deal.

For heating a home efficiently, one approach is a rocket mass heater. It does require burning firewood, but if that's an acceptable/desirable quality, this technology seems far more efficient than standard fireplaces.

https://en.wikipedia.org/wiki/Rocket_mass_heater

I have thought about that but it’s a bit too much custom work to add into a passive house.

I might try one in a future garden shed/office.

I'm in the UK which has one of the oldest/energy inefficient housing stocks in Europe.

After buying a house built in 1890 I've been made more aware how poor they can be. After replacing the old secondary glazed windows and replacing the old inefficient gas boiler, I'm moving onto replacing the front and back door, and insulating the suspended floor, walls and room in roof. The walls are solid whinstone about 600mm thick which I'd have expected to be a good insulator but in reality they're a thermal bridge.

For generation, I've reserved a spot in Rippleenergy's next co-op turbine [0]. I've been looking into PV/solar thermal/solar battery combinations as well as heat batteries. Sunamp's looks interesting [1] and phase change materials in general. Living in a high latitude (Scotland) the benefit in Winter is more marginal but I'd be happy with simply covering the cost and having peace of mind where the energy came from. PVT panels look interesting if not well-known/scarce.

There's so many parts to the answer it seems like energy advisors could be more of a thing in the same way financial advisors are plentiful.

[0] https://rippleenergy.com/

[1] https://sunamp.com/thermino-thermal-storage-for-domestic-hot...

The next most effective thing to do is External wall insulation. However that'll mean that you'll loose the whinstone look. (unless you pay a _lot_ to get whinstone like shims put on after)

The alternative is to have internal wall insulation: https://www.insulationsuperstore.co.uk/product/vacutherm-vac...

This is as effective as ~150mm of rockwool, but only 20mm thick. So this can be stuck behind plaster/plasterboard.

but its not easy to work with, or widespread yet.

Yes, it's one of the top recommendations (internal wall insulation) on my EPC and have had a survey. 60mm PIR boards would be used. Turns out I wouldn't have to sacrifice much space but would have to pay a bit extra replacing the cornices.

There are some regional grants in the UK that can cover a large portion of the amount. For me, it is £7.5K, with the quote I received at £9K. This would not have covered the kitchen or bathroom.

Going by EPC recommendations and numbers alone, I can reduce my energy requirement by about 40%.

Had to sign up for this. Take extra care to use appropriate materials for a house this age or you'll create more problems than you solve. Solid stone walls need to breathe!

Make sure you've spoken with a surveyor specialising in heritage property too.

PIR boards are almost certainly unsuitable.

https://www.victorian-house.co.uk/ (be sure to pick up a copy of the Haynes Victorian House manual, it's a gem)

https://www.lime.org.uk/community/boards-insulation.html

I'm currently having to undo poor choices of modernisation on a building of the same age, which caused tremendous problems with damp.

Thanks for taking the time to sign up.

I intend to use rockwool for the floor and roof crawl space.

Luckily I have a relative in the field who can share advice. I am conscientious of the condensation issue. There's a company local to me who use hemp boards which are porous. What you say is definitely something to consider given the extent of work involved, and to possibly undo.

Another good resource is https://www.neighbourhoodconstruction.org e.g their page on Thermal Envelope > Bio aggregate https://www.neighbourhoodconstruction.org/bio-aggregate/

Be super careful internally insulating an old house. This can cause _a lot_ of humidity problems if not done _exactly_ right. Very often, there is no way to do it exactly right!

I would recommend you to consider breathable internal insulation materials, combined with breathable finish layers of course! Some hints.

Roof (or attic floor) insulation is the most important. I imagine those have been done properly already.

Walls. There's industrial products for walls, like Xella Multipor. You may also want to have a look at eco products, especially if working on the place yourself. Hempcrete is a fairly forgiving material that works rather well for this purpose. Rather expensive to have it installed, but easy to do yourself.

Ground floors. Have a look at foam glass [0] insulation. It both stabilises and insulates, is moisture and fire proof, not horribly expensive and saves you from having to put in a layer of concrete. Not super well known yet, but growing in popularity. A wonderful material and super easy and forgiving to work with. A no-brainer really in many cases...

[0] https://en.wikipedia.org/wiki/Foam_glass

The one key rule that you should always follow is to have your water-impermeable layer on the warm side of the insulation.

So, I'd recommend against breathable internal insulation, because that will make your solid wall (water-impermeable layer) colder, but still exposed to the humid inside air, and this could cause condensation on that cold wall. As an example of this, I have rubbish double glazing, and when the temperature drops outside, if I have just the curtains drawn (which don't really provide any insulation) then I'm fine, but if I lower the thermal blackout blinds, then I get loads of condensation on the inside of the windows, which I remove with a window vac in the morning.

Breathable external insulation is less of a problem, because it warms up the wall, while exposing it to the comparatively dry air from outside, so you shouldn't get any condensation.

Agreed, houses with insulation have a vapour barrier behind the plasterboard for this reason: counterintuitively, the warm internal air carries a lot more moisture than the cold air outside. The partial pressure of water vapour is higher inside the house than outside, so the dew point of the internal air is higher than the outside temperature (dew point depends on water content).

If there's a way for that moisture to diffuse through the wall from inside, through the insulation, to the cold structure (which would be colder than before due to the internal insulation), the conditions are right for condensation to form. Those conditions are: surface temperature ≤ dew point.

Condensation can be prevented by a combination of:

1. Reduce the rate of moisture diffusion from the interior (seal the rooms and use a vapour barrier)

2. Lower the dew point of the air in the "cold" structural areas by ventilating the cold space to outside, so the moisture can exit (this is why houses have air bricks, vents in the roof, etc.)

3. Prevent the building structure from being colder than the internal dew point (i.e. use external insulation)

> The one key rule that you should always follow is to have your water-impermeable layer on the warm side of the insulation.

This very much holds true in 99% of modern homes.. except if you build your entire wall breathable. That is how we did our walls. From inside to out:

- breathable paint. Lots of conventional options available. We made a really nice casein paint with low fat cottage cheese and lime paint as the main ingredients :-)

- lime plaster. 1/3 slaked lime powder, 2/3 sand.

- 1.2m of straw

- lime plaster

An easier solution is plasterboard already bonded to PIR or XPS. The XPS is cheaper and I don't think it will make a massive difference depending on all the other challenges like windows and doors. You can simply stick this to existing walls with adhesive foam and then dry-line or skim the boards afterwards.

To do it well, though, you will often need to cut out/remove any laminate flooring so the boards can meet the floor and they won't do anything about leakage between floors, which can be significant.

> plasterboard already bonded to PIR

As you point out they are normally ~25mm or so of EPS/XPS. which doesn't do _much_, especially compared to 600mm of stone. Plus XPS is pretty flammable, so with electricity cables sandwiched between it, its not a great thing to have inside the house.

I followed your link, but am confused and/or doubtful:

how do you replace 150mm of rockwool with 20mm of anything other than a good vacuum? It says that they are 'very low internal pressure' - but if it contains any kind of gas (which i presume it must do - air if nothing else) then the conductivity does not depend on pressure until the mean-free-path has increased to be > the width of the container.

Is this product real? What is it about the physics that I am not understanding?

And how do you maintain the 'very low internal pressure' over the decades that you will need it for?

Thanks.

It is a good vacuum. They work but are expensive and a single nail destroys the whole panel, but maybe cheaper than the loss of floor space.

From what I've seen, its basically a honeycomb with a thick plastic coated foil to act as an atmospheric barrier. I came across it from a number of sites, but I've not managed to get any samples yet.

> And how do you maintain the 'very low internal pressure' over the decades that you will need it for?

now thats a million dollar question. I don't know.

> conductivity does not depend on pressure

I think it might be fumed silica aerogel at about 0.1 bar.

This paper describes the use of the same material for building insulation:

https://www.researchgate.net/figure/a-The-thermal-conductivi...

I suspect the key issue will be maintaining that low pressure for the ~100 year lifespan of the building. Perhaps future versions will come with micro pumps so that once per year the pressure can be pumped back down to 0.1 bar. Looks like for about a dollar you can buy a little 3 volt vacuum pump. One per panel out to do a decent job.

https://en.wikipedia.org/wiki/Vacuum_insulated_panel Looks like the thing. So, yeah, very good vacuum. It's apparently decades for the lifespan, but much of it boils down to the materials being used.

I work on energy systems modelling and how domestic thermal performance interfaces with that - the UK has not just "one of the oldest in Europe" it actually has the oldest in the world. Many European countries had a lot more post WWII construction so at least have cavity walls (even if in many cases not filled until later).

My understanding was that cavities should actually not be filled, since they allow water to drain out. Is that incorrect?

The issue is will the cavity system allow water to penetrate to the inner leaf which is bad and will cause internal dampness.

Cavities can be carefully partially filled with some type of insulation which allows the water soaking through the brick to evaporate and drain back out.

The standard technique is to use blown in EPS beads which allow for drainage downwards, reducing the chance that any water loading will make it through the insulation layer and to the inner leaf of the wall.

Problems with cavity insulation are often caused by:

-Treating walls which have a large amount of debris in the cavity, leading to water bridging

-Over-filling cavities which also leads to water bridging

-Treating walls with very large amounts of rain exposure, especially to driving rain for extended periods of time since this will lead to saturation of the cavity insulation system which may be unable to dry for months at a time. These walls should be externally insulated and clad instead.

In the UK context for example, houses in Wales and parts of the English South coast, the whole Southwest, the East of Scotland, and most of NI are in zones 3 and 4 in terms of wind driven rain exposure.

In zone 3 and 4, installers are required to carry out an assessment of site conditions and of cavity thickness as well as exterior wall finish. Older houses might have 50mm cavities, new properties often have 100mm or 150mm cavities. Obviously that reduces the changes of water soaking through.

Approved Document C allows a full fill of insulation for a 75mm cavity on a fully rendered wall and on a 50mm cavity if clad with rain impervious material but requires 150mm for bare masonry.

Thanks for the detail! I have a 1930s house with, I think, unfilled cavities. I’ve always been put off looking into insulating because it seemed potentially harmful.

I wish more municipalities would mandate tighter homes with good ventilation. Recently when searching for a new home it was so dishearting to see brand new developments where the homes had standard insulation, bad orientation for things like solar and passive heating and giant fossil fuel based heating systems instead of heat pumps. I decided to instead go the oppostie direction and buy a 1960’s split level that I am modernizing.

It’s been quite a challenge to retrofit, we really need to be building to a higher standard for new stock. While renewable energy is all the rage this rarely gets a mention.

In America the latest building craze seems to be a veneer of beauty over bad functional design, and a strong mentality of "fuck you pay me" from the seller.

What do you mean "latest"? Hasn't it (almost) always been like this?

Some houses used to be built on nice plots of land with non-shoe-box design, but I would argue that paying 1.5M for a "new" home depot material house on a postage stamp of land that will literally collapse when the particle board that supports the drywall gets wet... is not very good value for money.

It happens, youtube has the proof of it sadly!

>>Some houses used to be built on nice plots of land with non-shoe-box design,

Yes, but I feel like even "back then" that was an exception rather than the norm. There is a LOT of very poorly built houses around, and it's not just the problem with modern construction. Modern house prices and scarcity has made it worse, sure, but it feels like "built to the cheapest possible standard" was always a thing.

Yep, the flippers and the cash-hungry are riding this high as long as they can. It's bred quite a bit of entitlement but with the bonus that their poor attitudes are rewarded with large sums. This will happen (and has been happening) as long as housing is an investment vehicle with profit potential.

I can live with flippers and the cash hungry, since they mostly just do cosmetic repairs and they take some considerable financial risk.

But I absolutely despise big corporate builders who hire junkies as laborers and conmen as project managers. They will cut every corner, deliver late, charge a gigantic premium, and not answer your calls after you've taken delivery.

Also: It's illegal to build multi-storey housing in large parts of America. You know, the kind where you have stores on the ground floor and apartments above. Illegal and actively NIMBYed against.

A grocery store for a neighbourhood, within walking/biking distance? Illegal, against zoning laws.

> with good ventilation

Mandate windows?!

> heat pumps

That means (if I understand you correctly), fans. That is noise pollution - some will not have it, and some will not bear it. And (after experience), heat pumps can be inadequate for heating: they can raise a temperature, not warm the environment.

> That means (if I understand you correctly), fans.

It does not always means fans.

Geothermal or aquathermal heat pumps are fan-less, very silent and performs amazingly in cold climate. I have one home.

Windows>

Heat exchangers can be up to 90% effective at saving heat, while window ventilation will be 0%.

Noise pollution>

In my cold climate, whoever goes with heat pumps - they usually go with "air-water" systems. Meaning only outside you have fans and inside you have your typical floor heating.

Much higher than 90%. The one I had in the passive house I lived in was specified to 98% at most temperature ranges. I guess most of the time the temperature difference isn't that large anyway (<20C) so they will lose next to no heat.

Modern air or ground source heat pumps tend to be quiet, even silent, at least according to some deep dives down the Youtube rabbit hole on passive houses. Check out the "Moonstone house" on Youtube for example.

https://youtu.be/sSE8PurhfQs

My neighbour has a air heat pump for a ~200m2 house with good insulation, but not a passive house. It's at the edge of his property so I regularly pass it. I'd say you need to be less than a meter away to hear it at all, and even then it sounds like a fan. There's absolutely no vibration or so.

However, the house is new, let's see how it the unit sounds in 5-10 years.

We have a heat pump from ~2008 about a meter away from the outer wall of the house and I don't recall ever hearing it from the inside. You'll hear it from a few meters on the outside, but it has never been a problem. It's able to heat a ~250m2 house in -10°C weather.

That being said, do yourself a favor and do not get a heat pump connected to 'the cloud'. Our heat pump can't be fully controlled locally (some functionality is web only) otherwise I'd put it offline. They unnecessarily performed repairs on the heat pump to the tune of 500€ because their servers had issues.

You're wrong on both counts.

Windows don't make for very good ventilation. They are prone to letting in either too much or too little air, which means you're either wasting a lot of heat, or are not getting enough fresh air. Mechanical ventilation with energy recovery is far superior. Windows, of course, are great for letting in natural light and for creating a sense of spaciousness etc.

Heat pumps don't always need big fans, only air source heat pumps do, and even those can be made to be pretty quiet. Not much louder than a gas furnace.

They definitely can warm an entire house (in fact, they do so on a regular basis in many houses in many parts of the world), even in the coldest of climates. Heating a Passivhaus requires only a tiny unit (except for hot water, but let's ignore that for a minute).

> Windows don't make for very good ventilation

The point was not with ventilation quality, but with the feasibility and compromises of alternatives. (The strict point was with defining "mandating good ventilation".) Mechanical ventilation with energy recovery may be far superior, but if that means constant noise it will be an issue - to some, a radical issue.

> They definitely can warm an entire house

And I have stated that they can be perfectly inadequate and ineffective (explicitly: which is not contradicted by your statement). Evidently, it will depend on implementation, and again on the expected effect (where temperature is only a partial factor).

Speaking of implementation, I have been in hotels where the heating pumps were unbearable in that they made the room tremble and clearly vibrate.

So, when one speaks of mandating technologies, there are critical implementational issues to be remembered, and the "embrace" drive is to be immediately criticized (just applying one's usual duly Reflection). It is relevant that I have seen in the past legislation mandating some technologies only halfway trough (e.g. mandating valves without mandating pressure control systems), creating immense damages on large territories.

Edit: also:

> Heat pumps don't always need big fans ... Not much louder than a gas furnace

You have not stated they are perfectly silent, 0db - in fact, you seem to suggest the opposite. As said, some do not tolerate background noise.

I do not see where you read anything wrong.

"Mechanical ventilation with energy recovery may be far superior, but if that means constant noise it will be an issue - to some, a radical issue." I've installed this in my house, it is virtually silent. This is for ~200m3 of clean air/hour. If I turn it on higher you can hear it a little.

> virtually silent

Decibels?

I have seen air purifiers publicized as exemplary silent, and people unable to bear the noise of the minimum fan speed.

There may also be a matter of the exact sound - maybe some are less disturbed by (say) a hum instead of a hiss; it probably has to be tried.

While I don't have mechanical heat recovery ventilation, I've been in lots of apartments and houses that do (it's virtually mandatory for new builds here). You won't know it's there unless you're in the room that the device lives in, and even then it's not loud.

A well insulated house needs some sort of mechanical ventilationm otherwise you will have problems with humidity and - in worst cases - mould.

The ventilating units are usually placed in the basement and are not noisy (but need some maintenance and cleaning).

There are heat pumps that simply heat water and are suitable for underfloor heating, no fans.

Underfloor heating is usually "slower" (compared to air heating) but works just fine, actually better.

If you ventilate purely via windows, you'll need to always pay attention to avoid any mould. With a ventilation system hooked up to a heat exchanger, there's basically zero chance you'll ever experience mold.

A heat pump can be air source or geothermal and you can use them to create hot water for a hydronic system or forced air (ducted or non-ducted). So not all of those will create the same noise levels. As they can be virtually any size and now work well at very low temps, I don’t see how they can be inadequate for heating. I’d have to hear of an example.

Up in the Northeast U.S. they are still putting oil fired boilers in new homes since gas isn’t super common outside of larger cities. I’d like to see more new homes have solar, heat pumps and possibly even stationary batteries in the future. These are going to be essential if we want to get off fossil fuels.

I think this is one of those things where people generally agree that better insulation and lower energy costs is a good thing but who pays for it?

In the UK, there is a constant demand for "affordable housing", which is caused by governments not controlling the housing market from either foreign investors or also people using the housing bubble to buy up loads of properties over time forcing others to rent.

Bearing in mind how much profit a lot of home builders make, increasing the regulations is likely to add at least £20K to a basic house, significantly more if you include mechanical ventilation, triple-glazed windows and heat pumps (perhaps +£50K), which is some cases will be 50%+ of the original cost!

Another major problem is the quality of building in the UK, mainly driven by a lack of tradespeople, and simply not having the skills to install to the quality levels required by thermally efficient houses like installing a membrane with zero holes in it, using the correct tapes, designing, installing and maintaining heat pumpes and various other things.

I think these challenges will get better over time but that is probably why governments aren't keen to make large improvements in energy-efficiency regulations.

> I think these challenges will get better over time but that is probably why governments aren't keen to make large improvements in energy-efficiency regulations.

This is probably true but it's still backwards. The state should want to improve the affordability of housing and should consult with industry on which measures can be introduced but ultimately the state must introduce the new regulations to help drive the market in the direction of continuous improvements to the housing stock's long-term affordability. I think if they shirk this then they simply aren't doing the job properly.

>Bearing in mind how much profit a lot of home builders make, increasing the regulations is likely to add at least £20K to a basic house, significantly more if you include mechanical ventilation, triple-glazed windows and heat pumps (perhaps +£50K), which is some cases will be 50%+ of the original cost!

The sales price of houses in the UK (and elsewhere) is driven by the market and there is a low amount of released, buildable land and a lot of demand in the Southeast. The land value (a large component of the value) is not actually set in an independent market but is based on the expected sales price minus construction costs and development costs. Therefore increasing the built cost of properties will decrease the value of land likely to receive planning permission without affecting purchase price by much.

The marginal cost of thicker walls is also very low (especially compared to retrofit costs) so the impact on construction cost is nothing like £50k.

> Another major problem is the quality of building in the UK, mainly driven by a lack of tradespeople, and simply not having the skills to install to the quality levels required by thermally efficient houses like installing a membrane with zero holes in it, using the correct tapes, designing, installing and maintaining heat pumpes and various other things.

It's an incentive and delegation problem. I'm in the US, and have been through three large renovations to family homes, and the trades I've worked were (nearly) all HIGHLY skilled, but had zero incentive to exceed energy efficiency goals required by code. The small business contractor needs to complete your project, get paid, and move on to the next. The best ones don't have any extra time - they're prospecting clients and building estimates for the next big project.

I agree with the sibling comment this is an incentive problem rather than a skill problem. If house builders can cut corners they will. If they can sell a house for the same cost without the fancy new insulation gear they will.

This is why your bit about regulation is needed because otherwise the things you list won’t happen. Home chargers are a good example which the govt deemed necessary for new builds, the skill will be there for that and without the regulation I’m not sure most builders would have bothered, leaving people to retrofit one further down the line paying a higher cost. The skills for heat pumps will organically grow as regulation kicks in too.

> why governments aren't keen to make large improvements in energy-efficiency regulations.

The govt have been consulting with various business and institutions on future building standards you can view their response here: https://www.gov.uk/government/consultations/the-future-build.... But from it we've already had EV charging point requirements, ban on gas boilers, new homes in England will have to produce around 30% less carbon emissions, plus raising the standard for insulation.

Interestingly the previous Labour government had raised the standards for insulation but one of the first things Cameron did was abandon that legislation. This stuff is so frustrating.

It saddens me that construction quality is almost irrelevant when building a new building nowadays. The profit difference between a well-isolated passive building and one that merely meets the minimal standards, is often very small, so why bother building a passive building?

My personal interest in passive buildings generally revolve around maintenance. Passive houses seem to require far less maintenance.

>The profit difference between a well-isolated passive building and one that merely meets the minimal standards, is often very small, so why bother building a passive building?

People making decisions about which contractor to use (both for public and private projects) are often mandated to choose the absolute cheapest bidder, sometimes with the ability of choosing a different one if they file mountains of paperwork explaining why.

That's what norms are for.

If minimal thermal requirements are written in the law, even the cheapest builder must build a highly insulated home. In my country, it's mandatory to have well insulated home, to prove (with tests) that you respect the norms, and it's also mandatory to have renewable heat source (mainly heat pumps). Sure, it costs a little more, but with the rise of real estate prices, it's still way cheaper to build well insulated houses.

The building cost since those new norms increased about maybe dozens of thousands euros. It's not even a lot given the exceptional thermal comfort you get from your money.

> Passive houses seem to require far less maintenance.

Interesting! Could you explain a bit more on how you came to this conclusion?

In general, this conclusion comes from the notion that a passive house has fewer moving parts and requires less attention. A poorly insulated house demands that you take more active measures to ensure that it keeps a positive temperature (so water pipes don't freeze), this is extra pertinent should the power go out. A well-insulated house is also likely to have fewer points of failure (water getting into cracks and whatnot).

A proper passive house generally only has one maintenance point, which is the ventilation / air filtration system, and temperature control is easy. You don't have to worry much about the insides being too hot or too cold, as it should keep whatever temperature you set regardless of the weather outside.

With all that said, you should generally take everything I said with a grain of doubt, as I'm not an expert, and someone could well shoot down all my points in the comments. ;-)

My prime goal with any house I buy is to make sure that I have to do as little as possible; never worry about water being in the wrong place, and never worry about the power bill, or temperature in general.

Ah I see, that makes sense.

I've always found Passive Haus design interesting although the (expensive) single point of failure that lies in the air pumps scares me a bit.

First of all, if you build a PassivHaus in normal climate (not cold) you will be amazed to see that you do not need a heat pump, you can just use normal electric boiler for hot water and use electric underfloor heating mats for heating, or infrared panels mounted on the roof. On the other side, air-to-air heat pumps have gotten cheaper by the year, you can buy a decent heat pump (NIBE) with about 4500-5000 euros.

Electric boilers are extremely energy inefficient compared with heat pumps. If you built a Passive House, not going the extra mile for a heat pump seems silly to me. Not to mention that heat pumps can easily protect you against heatwaves (should any happen).

True Passivhaus needs less than 1000W of heating ever; at that point the expense of heat pump is unnecessary for something rarely used.

Exactly what coryrc said in his comment, for a PassivHaus you recover very slowly the cost of the heatpump and if it brakes once in 10-15 years while it takes to recover the investition... you will never recover it.

Personally I've addressed that concern with a CO2 alarm in every room (which you should have regardless, so I don't count that against passive houses). I suspect that there exist ventilation fallback solutions that can address a power failure scenario, but I've yet to find any viable ones.

It should be possible to have a system that generates automatic airflow should power fail.

Best ones I've found are solar panels, or geothermal power generator (geothermal is generally really amazing for everything), but that still leaves mechanical failure.

That said, it takes quite a bit of time before ventilation failure leads to a dangerous CO2 buildup. And the addition of having a single entry point for air means that it's easy to filter my air through a HEPA filter, ensuring top quality air all year round.

The houses in the article have a lot of wood and decking.

New Zealand is savage on exposed timber. I have tried multiple products from expensive to cheap and have the same result on all.

A deck which gets rain and faces north west needs re-coating every 6 months to 1 year. The combination of heat, UV and water is just savage.

Have you looked at modified woods like Accoya? (50 year guarantee above ground, 25 in water)

Thanks - I hadn’t.

I haven’t had any degrade to the stage where it needs replacement, I just have to keep maintaining.

I’ll look into it further, the product looks impressive.

It's good stuff - but not cheap.

For decking where you're going to have to clean it yearly anyway, I wouldn't bother (no real effort to just add on some maintenance) - and probably works out cheaper even with a few replacements over decades.

Where it shines is where it's a pain to replace and a nice bit of weathering is what you're after (say the eaves on a roof) - not too expensive to run a plank around the perimeter and no ladders/scaffolding/treatment required for the rest of your life.

The reason the stuff lasts so long is it's chemically gone from cellulose/wood fiber to acetate.

There's a lot of issues with using it aside from expense; anything touching it will be impacted by the acidity of the wood, so you'll want to use things like stainless steel.

It's a great wood, but it's not all roses. The other thing to keep in mind, the process behind it doesn't HAVE to be applied to New Zealand or Chilean radiata pine, they only use that wood as it's more marketable and people are more likely to stomach the costs.

Something to also keep in mind the wood is only treated on the outside. If you cut into it, for example the endgrain on every plank you buy - it'll need to be sealed just as regular radiata pina. When "perennial wood" was originally sold decades ago, people installed it expecting zero maintenance and then found their decking started to rot less than a decade later. Keeping that in mind, similar issues can arise if you sand the wood.

> It saddens me that construction quality is almost irrelevant when building a new building nowadays.

Depends on where you live; houses in the Netherlands are built to high standards when it comes to things like insulation, build quality, electrification, etc.

Are houses in the US still built with 2x4's and drywall? You'd think they would move to what we have here in the Netherlands, mostly sturdy concrete blocks, insulation layer, and a pretty brickwork or brickwork-looking facade.

I mean the amount of clips I see on the youtubes of people breaking walls make me cringe. A wall should break you, not the other way around, :D

Some countries have comparatively high building standards, but none (that I'm aware of) come close to a Passive House standard.

My gripe isn't as much what the minimum requirement is, and more the incentive to never go above it, because property prices are generally only going up with little regard to building standards.

> Are houses in the US still built with 2x4's and drywall? You'd think they would move to what we have here in the Netherlands, mostly sturdy concrete blocks

Do you mind explaining why you feel this way? There are definitely benefits to reinforced concrete such as durability and resistance to certain natural elements, but as far as I can tell modern fire-treated wood construction tends to be nearly as safe in fires or superior in earthquakes, has better insulation, and is more ecological during the construction process. Overall, I would prefer reinforced concrete, but it’s more for the “qualitative advantages” as it feels more reassuring to the touch.

Speaking of electrification, one complaint I have of most construction in at least continental Europe is the consistent dearth of electrical outlets in residential settings. Living in Switzerland for years and visiting other countries, it seemed like an extension cord across the bedroom or living room was nearly always needed due to awkward and very limited outlet placement. The fire code in a state like California seems to have much stricter mandates to prevent this sort of thing.

> Speaking of electrification, ..

Probably because the housing stock in continental Europe is older and therefor much more often retrofitted with modern electricity. Newly build houses won't have that problem. Although I'm not aware of fire regulations having an effect on the number of outlets in a room, in my region (Belgium).

> the consistent dearth of electrical outlets

In France, it was the case in old houses.

On new constructions, a minimum number of outlets is required (3 per bedroom, 5 to 7 in the living room, 4 in the kitchen, 1 in every other room). This is in addition to dedicated circuits (washing machine, oven, dishwasher, heating, lighting...) which may have their own outlets. RJ-45 networking is also required (1 per room) but unfortunately, it is often designed poorly and barely usable except for a phone landline.

These are minimums. And it is typically what you get in standard apartment buildings. But you can have more. I have about double. A friend of mine has an outlet every 50cm!

> I mean the amount of clips I see on the youtubes of people breaking walls make me cringe. A wall should break you, not the other way around

The external wall un old French house can easily reach 55/60cm of pure concrete mixed with stones in cold places.

Trust me, it will break you and specially break your will to make any hole in them ^^

> I mean the amount of clips I see on the youtubes of people breaking walls make me cringe. A wall should break you, not the other way around, :D

Why? I think calculating heat loss, noise levels, wireless signals, fire resistance, ecological cost, etc would be decent metrics to judge the merits of a wall.

But if you are living in civilization, I do not see why the wall withstanding the impact of a body is something I should care about. Also, there is almost always an external envelope of exterior siding plus plywood sheathing that I have never seen penetrated by an individual without tools.

I doubt the maintenance part. I lived in one and experienced more maintenance. You have the heat exchanger as an additional moving part which needs cleaning, new filters, etc.

Also, you need a perfect seal between inside and outside. So any cables going outside (blinds, air conditioning which you'll still want if it's 40C outside, etc) needs to be sealed and is thus much harder to replace or repair.

In 1989 my grandparents built a home with 12" thick walls (6" was normal at the time, in the area) and carefully vapor-sealed the entire house, taking extra special care to avoid holes which would let air move through the house in an unplanned way.

They paid extra (a lot extra) for the highest insulation value available for the fiberglass rolls they installed in the outside walls. They double-stacked the insulation, as well, which is why they built the walls so thick.

They poured the basement foundation on top of layers of foam insulation, and used piers (I don't know what they're called) down to the bedrock for structural integrity; the majority of the outside of basement floor was in contact only with insulation. Only 16-20 8" columns went through the insulation down to bedrock and could be good conduits for heat to the earth. All of the walls in the basement were double insulated from the earth they held back.

That house was heated entirely by the heat that the water heater released through its insulation. Once or twice a year they would light a candle on the dining room table, to bring the heat back up if it ever got below what they felt was comfortable. Most days they had windows cracked open on opposite sides of the house in the middle of winter because it got too hot even with the furnace turned off entirely. It was never less than 75F in that house, even when it was -15F outside. I spent months on end in that house, just wondering when the furnace would come on. It never did. Not once while they lived there was the furnace ever needed. They lived in Missouri, US.

Years later my grandfather realized that he had left the petcock which allowed hot water to circulate to the radiator over which air was blown and heated to circulate heat throughout the house closed for over a decade -- since the house was built. "I knew I wouldn't need this damn furnace. Building code requires it, and I fought that but lost."

If you're careful, thoughtful, and determined, you can make a little bit of heat go a very long way. They were tired of paying heating bills. They paid to get rid of them, but they were rid of them.

> In 1989 my grandparents built a home ... and carefully vapor-sealed the entire house

In the upper Midwest there were a number of homes built this way in the 80s/90s. 10-15 years later they all had black mold (nasty health hazard) growing in the walls because moisture couldn't escape from the house. All homes are now required to have air-to-air heat exchangers for this reason.

Its not moisture, its general ventilation. All houses should have formal ventilation systems to exhaust CO2 and control humidity secondarily.

While I certainly dream of building a true passive house, it is much more reasonable to follow the Pretty Good House approach, in it's current 2.0 version described here: https://www.prettygoodhouse.org/pgh-20

As with most engineering efforts, the last 20% of optimization tend to be costly. But covering the basics (mainly around insulation and air-sealing) has a huge impact already without increasing upfront costs by the same ratio.

Also the wall/roof assembly needs to match the climate for the region, mainly because of the dew point and how it relates to temperature and moisture differences between inside/outside. https://en.wikipedia.org/wiki/Dew_point

Reminds me of 'Earthship Houses' that are completely off grid, recycle their waste water to grow crops, are built using repurposed car tires and grow their own food.

There is a community in New Mexico https://www.youtube.com/watch?v=wgUkjbMhF18

And even some in Canada https://www.youtube.com/watch?v=EAvY5JeMz9w&t=62s

Yes! Any they typically make good use of passive + solar thermal management. For example automated window openings to draw heat through etc

Also reminiscent of a Canadian (?) advocate from the late 20th century, can’t remember his name. Actually built a huge passive house with a large internal greenhouse and a small stream for air quality.

that Earthship in Canada is owned by my best friends parents! It still get's pretty cold in the winter (Lethbridge winters are incredibly cold and windy) so it took some acclimatizing when they first moved in. I think they have improved it somewhat since then.

Earthship are very low density unfortunately.

Good at reducing the environmental and economical impact of the house itself but now you have to drive a car instead of living car-free in a walkable city.

Good point. I wonder what the environmental impact is of high density housing in cities vs low density (earth houses).

I think it probably does make sense for rural communities.

Ha, I volunteered to build Earthships in New Mexico in 1995 during my orientation week at college. Fascinating community.

Thanks for the reminder.

I wonder how these "no heating"/"no cooling" homes work in situations like mine: my wife is permanently freezing cold, sitting around inside with multiple layers on, sometimes a blanket, and the heating on full-blast while I am walking around in shorts and t-shirt sweating?

I.e. people have different ideas about what a comfortable temperature is. In my wife's example it seems like unless she can actually "feel the heat" as it were, she is not comfortable.

Sounds like one of you might have a health condition. She could be underweight or anemic, you could be overweight or etc.

I think one of them is a woman.

I'm pretty sure that totally healthy people also prefer different temperatures.

And it's common that women prefer it slightly warmer; men do have a slightly higher metabolic rate on average even when they have the same height/weight, and those extra calories that the body uses end up as heat.

It's common, but I find it strange considering women have overal much more fat, so you would expect the roles will be reversed.

Maybe not a health condition, might just be the body's set point.

There are three biological states: body is cold and needs to warm itself, body temp is right (no effort required), body is hot and needs to cool itself.

I was born in hot southern climate, my wife in a cold norther climate. For me, "body is cold" is rather unnatural and uncomfortable. For my wife, "body is hot" is the same. Her internal furnace is always on, my internal cooling system is always on.

She is happiest at 18C ambient, I am happiest at 22C.

If you want a biological mechanism to explain this, it's called epigenetics, and the key factor would be the environment your mother was in while you were in the womb and she was forming your body.

I'm not 100% sure of this. Totally anecdotal but... I was born and raised in a continental climate, where during winters most day you would stay between -2C and 1C and sometimes you can get -10C during nights. I remember feeling cold but it wasn't that extreme.

Then in my twenties I moved to a warmer, near the sea place where a cold winter is when you get 2/3 Celsius degrees in the coldest night and after a few years of that life, now when I go back the place where I was born in winter, I feel fucking cold (and I have special winter jackets for that).

My anecdote is the other way around. I was born in the subtropics, grew up w/o A/C. It never got below freezing.

I moved to a colder climate. The first few years I complained that the summers were never hot enough. I expected and wanted to walk out of an A/C'ed building into a wall of heat and humidity.

Now I'm used the colder weather, and find 15C/60F to be a wonderfully comfortable temperature.

And nowadays I find winter is the only season to visit where I grew up, if I want to feel comfortable.

I figured it wasn't epigenetics or some such, but rather that your body could adapt to it. I remember once when it was -23C/-10F for a week then warmed up to -10C/14F. I rolled the windows down on the car because I felt so warm ... and then I noticed the bank thermometer and was surprised.

It's fairly normal for different people to prefer different temperatures, and to a large extent it's probably a learned thing. In particular, the idea of what normal room temperature is varies quite widely around the world.

Not OP, but my wife and I are both quite thin and have no health issues. She is always colder than I am.

You can still control the temperature in a Passivhaus, the difference is just that you need much less energy to heat it.

It won't solve the problem that people prefer different temperatures, though.

It's the opposite for us; I'm the one feeling cold, while my wife is comfortable. I started wearing a layer of thermal underwear in the cold seasons to compensate.

You must embrace the cold. Any attempt to warm yourself will just make your body expect warmth. Never turn on the heat, and you'll slowly adapt along with the seasons. Maybe set the thermostat to 33F so that the pipes don't freeze...

The human body doesn't "expect" anything, it simply must maintain its core temperature. If the temperature of the environment goes lower, the body responds by

1) increasing thermogenesis, i.e. convert chemical energy to heat through metabolism

2) reducing heat loss through the extremities by reducing blood flow there. In other words, you get cold feet and hands etc.

For people not bothered by cold, presumably it's mostly (1). For me, being skinny and not having a big appetite, it seems to be mostly (2). I suppose I could get used to having cold extremities half the year. But why suffer if I can simply put on an extra layer of clothing? I don't see the point.

but you can change what temperature you are comfortable with. i have experienced that myself. coming from an area with cold winters and heating, moving to an area without heating, i found winters absolutely horrible because despite mild temperatures outside, having those same temperatures inside was unbearable. until i got used to it. more or less.

recently i visited a friend in the north who had heating. but he complained that their heating was not good enough, and i saw him wearing a jacket inside. i, on the other hand, felt very comfortable because his weak heating was warmer than my no heating.

likewise in milder climates people start to put on winter coats when the temperature drops a few degrees outside, while i, used to much colder temperatures am still running around in a t-shirt much longer than everyone else.

the primary problem with it being cold inside is that you are not moving enough. while i am fine to have no heating in most of the house, i am heating my office because there i am sitting for many hours without moving much.

For me, socks did the trick. I never had cold feet but always felt colder than colleagues in the office. An additional layer of socks made me feel warm enough to agree with the others on a thermostat setting. Still amazes me how much of an effect this had.

> about what a comfortable temperature is ... it seems like unless she can actually "feel the heat" as it were, she is not comfortable

You wrote it yourself... Comfort is not with the temperature (scalar quantity for C implemented roleplaying¹), it is with the "warmth", with the effect obtained in the internal environment, a quality you feel. This is why heat exchange feels ineffective compared to radiators. Sheer temperature is only partially indicative even outdoors.

Spend time in a car under the sun, in general, but even when paradoxically heated by the sun to a good internal temperature in cold winter, and see the reaction of the body.

(¹A memory cell with a scalar for "health", one for "strength", one for "agility"...)

To feel warm, radiation is more effective than temperature.

And it has to be the right radiation (hence the example of the (bad) environmental quality of a car under full sun).

From experience I can say that it works. Simply by using different clothes (as you described, t-shirt vs multiple layers). The only people who really struggle with no heating homes are those who need colder temperatures to sleep. I had several guests who complained that they'd like it cooler at night than during the day. However, that's not really possible if the house isn't really heated anyway and thus won't lose heat during the night.

Sometimes this is down to "micro" draughts rather than the temperature. Currently, I am sitting in about 19 degrees C inside and that should be plenty warm but in my T-shirt, I can feel very low level cold draughts caused by windows, small gaps etc. and some people are definitely more sensitive to these.

As others have said though, you can hopefully find a suitable temperature that both of you accept and it won't cost as much to keep it there.

Its all very well using environmental energy sources to heat and cool a building, but very little attention is given over to clearing the air. Besides the pollutants from cleaning products and product breakdown, CO2 levels inside a building can have a stimulating effect on the body, which kind of destroys the purpose of a relaxation of a home.

The passive house standard requires mechnical ventilation using heat exchangers to minimize energy loss. http://tepperarchitects.com/?p=522

Yeah but what is a healthy Air Changes per Hour (ACH)?

The building regs here in the UK are a bit all over the place, I had to direct some questions to the local authority planning dept because their legislation was like a poorly written computer program and they couldnt answer the questions.

The legislation doesnt quantify the risks properly imo, at least here in the UK.

This article is about passive houses, which have very good ventilation (they have to, because the building is hermetically sealed apart from the HVAC). So the air quality is much better than normal homes without a dedicated ventilation system.

The houses I’ve seen control the exchange rate with air quality sensors - so, if you are having a party, the ventilation speeds up, and when the house is empty it slows down.

That said, in the US the ACH rate is recommended at 0.35 by ASHRAE, see https://www.epa.gov/indoor-air-quality-iaq/how-much-ventilat...

Yeah but its not measuring the quality of the air. Houses are just passive particulate collecting devices, ie particulates travelling on the air outside, move into the house, meet a stationary or slower moving body of air, lose momentum and velocity and thus succumbs to the effects of gravity and hits a surface.

Considering woman have traditionally been the one's cleaning the house for the living abode for hundreds of years, why havent they come up with something better to filter the air inside a property seeing as there is this push to get females into STEM?

There was a big Thing in the neighbourhood I live in (built ~15 years ago) where this kind of two-way ventilation system did not work correctly; it did not have the right capacity on the one hand, and was too loud on the other (meaning people shut it off). But they're so well insulated that that was not an option.

My house has a one-way ventilation system, air is sucked in through vents in the windows. We keep it at the lowest setting though, again because of noise, but that seems to be all right for us.

> CO2 levels inside a building can have a stimulating effect on the body, which kind of destroys the purpose of a relaxation of a home

Citation really needed.

You know where google scholar, pubmed and wiki is? Or do you want to get into a discussion about under-carboxylation and dietary intake of nutrients, and CO2 blood saturation levels?

https://en.wikipedia.org/wiki/Hypercapnia#Tolerance

> You know where google scholar, pubmed and wiki is?

I know them quite well but this is a conversation on HN and people should back their claims here.

Well you can see that breathing is stimulated with rising CO2 levels, everyone knows this whether they have exercised or held a non-permeable bag over their head.

Its interesting because Climate Change aka rising CO2 levels will stimulate the population globally which then presents a new area of concern for authorities who like to keep control of a population. Hadnt thought of that until now!

You are throwing around the word "stimulating" in a very misleading way.

If don't have good circulation in your home your respiration rate is going up by an unnoticeable amount. The idea that this prevents "relaxation" is absurd.

Equally absurd to claim "presents a new area of concern for authorities who like to keep control of a population".

If anything it's the very opposite, where *high* levels of CO2 *decrease* attention and causes drowsiness.

- https://www.nature.com/articles/s41526-019-0071-6

- Karnauskas, K. B., et al. (2020) Fossil fuel combustion is driving indoor CO2 toward levels harmful to human cognition. GeoHealth. doi.org/10.1029/2019GH000237.

- https://www.sciencedaily.com/releases/2020/04/200421090556.h...

> there is no excuse for New Zealand homes to be damp, cold or drafty

Yet we build them this way over and over and over and over and over and over and over and over...

Lack of building regs?

I think a key issue is that generally the person designing a house isn't the same person who will be paying the energy bills in 30 years time.

Few people will pay a lot extra for a better insulated house.

The end result is that the cheapest insulation allowed by law is used rather than something that costs more today but saves a lot in the long run.

I wonder if a solution to this problem might take the form of "We'll sell you the house, and promise to pay half the energy bill for the next 50 years". Obviously there are issues with that... is there a better way to align incentives?

I think the assumption is that with regulations, the government can force builders and buyers to accept the higher standards and the associated higher cost in return for the common-good.

> I think a key issue is that generally the person designing a house isn't the same person who will be paying the energy bills in 30 years time.

Those who build homes must typically be planning on staying at least a few years in them though, say 10? Insulation is pretty cheap compared to running an AC in a poorly insulated home. Also it's not just a cost issue, it's more about comfort. Sleeping in a cool space without an AC blasting is worth something too.

The person designing the building codes though is the person responsible for the energy use and supply of the country, it's CO2 emissions and so on. So slowly getting more efficient building codes seems like it should be universal.

In Austria an architect build an office building completely without any heating at all [1]. And now after the first experiences he is doing it for clients as well [2]. It works.

[1] https://www.detail-online.com/article/house-without-heating-...

[2] https://www.world-architects.com/en/baumschlager-eberle-arch...

> Our designs combine generous ventilation with high insulation (140mm-thick wall framing combined with R4 wall insulation in the North Island – far above the Building Code requirements)

NZ North Island is pretty extreme in its non-extremeness. It's near perfect for building homes that don't need excessive heating and cooling. From a global perspective, 140mm insulated framing is nothing. In any colder climate (such as the nordics) or hotter climate (such as the south US or southern Europe) a comfortable well-insulated wooden frame home needs at least 300mm insulation. That's also the code in e.g. Sweden.

Checkout poroton, as a building material it is near impossible to beat - high insulation, low total cost, humidity seeps slowly thorugh the walls and termal mass is massive

> Even in places known for their extreme weather conditions – such as ‘hot ‘n’ cold’ Otago, wind-prone Wellington and sweaty Auckland – high-performance homes will stay comfortable and fresh all the year round.

All these places stay above 45F and below 80F. This is anything but extreme weather. You don't need any sort of special "high performance" house for this kind of temperate climate.

Living in a true hot n cold New England USA makes me jealous that anyone would consider this extreme. It's sweater n t-shirt weather. I consider hot n cold being 100F in the summer and 0F in the winter.

They mention that they avoid over sealing, for local climate reasons but an interesting technique/gadget for sealing the air barrier is to vapourize some caulk type stuff in the air and force air in through a fan. As the air escapes through small holes it fills them.

Apparently without this you need to be very careful while building, while this lets you go a little faster and sort it out after.

https://www.finehomebuilding.com/2013/05/15/a-shortcut-for-a...

There's also a recent development where just slapping on some solar panels can sometimes make more sense than extra insulation, in terms of cost and return.

Location and climate are very big factors when it comes to home insulation.

The South African Highveld for example has an extremely mild climate.

My house has no insulation in the ceilings, single pane windows, double brick walls with no insulation and air vents all over the place to the outside.

The house was built in the 70s I think, using construction methods appropriate for that time. So ot very modern.

I have no climate control in my house. And I don't need any. At the moment I'm considering some ceiling insulation, because in the middle of summer things can get toasty in the evening when the hot roof radiates back into the cool house.

South Africa here, it's not common to build energy efficient houses although it's gradually getting slightly better.

I'm busy changing all my windows to double glazed (single glazed is the norm, believe it or not) and proper insulation in above the ceiling.

Instead of freezing my ass off every winter it's now super pleasant, and it's cooler in summer. Such a non-brainer - I just don't understand why people don't do this more.

Note that the sun is towards north in NZ.

I'm kind of curious what weather range they are talking about.

As someone from Canada, i somehow don't think this would work over here in the -40 winter.

Canada was actually one of the early study and proving grounds for passive houses, due to the oil shock (look up the Saskatchewan Conservation House).

Sadly much like most other such actions, they were quickly discarded once the shock receded, but the german Passivhaus Institut was actually founded on the basis of that study and model house.

I lived in a PassivHouse in Germany. Didn't need to heat if it was more than 4C outside (less if more people were at home). I never experienced -40C, but at -20C it worked fine. Probably the only time all heating had to run to some degree 24/7. I'm sure that -40C would've been fine as well.

In the end it all doesn't matter. You build the house to some standard and then design the heating system to be able to cover thermal loss for the expected temperature range. In Canada you'd probably just add twice as much heating as you would in most of Europe. But especially at those temperatures, very well insulated homes will save a ton of money.

The only part that kind of worked less well at very low temperatures was the heat exchanger for the ventilation system. It didn't run at full capacity if it was well below freezing. But I guess there are other systems out there which are designed for -40C as well.

Does not work at all. In Finland we have disastrous situation with pre-90's "Bottle"-houses with air-tight insulation. Not enough circulation and dangerous mildew blooms.

All this lower 50's German crap about heat pumps and heat exchanges does not make much sense. Once again. Not a surprise.

The article shows off snazzy housing for wealthy people, but as far as I know all new housing finished in the EU as of 2021 is supposed to be built to these standards. So it's not restricted to architecture magazine, it's just regular houses.

See e.g. https://www.igbc.ie/nzeb/

Actually, article complains that Building Code is pretty low standard in NZ and that non-wealthy suffers as they live in not-so-well insulated houses.

But speaking from northern EU country - yeah, I don't see anyone here building non-insulated houses.

nZEB isn't quite the same thing as a passive house; a well-built passive house would qualify as an nZEB, but you could for instance, build an nZEB that had reasonably high thermal losses (thus not a passive house) which it compensates for with loads of solar panels.

That said, in practice most nZEBs probably will be passive houses or close; it's probably the most practical way to meet the requirements in most cases.

I really think many people don't pay enough attention to insulating homes they think solar panels, heat pumps etc.. But don't think of why the house is too hot or too cold. It's all just moving energy around cold is absence of heat but you hear of people say "cold is coming in" really it's heat escaping.

I'm going to try my hand at insulation my parent's home. Dad died last year he built the house and everything in it and on it. He was sick for 15 years so maintenance was difficult.

I'm looking at Rockwool for the attic most heat is lost through the roof. The pull down stairs are terrible for heat loss. Heat bridging is also what I want to tackle too I'll cover joists perpendicularly.

Stuffing the attic with insulation is easier than solar or a heat pump. For now.

I want to also to highlight the importance of the building airtightness (Air Changes per Hour) on the energy consumption needed for heating.

I saw an example at some point in one of PassivHaus presentation and it was like this:

0.3 ACH -> 1.74 kWh/m2year (for a 100 sqm house means, 174 kwh per year for heating)

0.6 ACH -> 3.49 kWh/m2year (PassivHaus limit)

1.0 ACH -> 5.81 kWh/m2year

1.5 ACH -> 8.72 kWh/m2year (Low energy house limit)

4.5 ACH -> 26.5 kWh/m2*year (typical house)

This is for the same house with the same insulation. Of course you cannot achieve this kind of airtightness without careful planning and using a lot of self-adhesive tape (SIGA, ROTHOBLASS and other manufactures that can guarantee its effectiveness up to 50 years)

Any tips for me? I live in Northern California in a house that (1) has an empty space below it, (2) single-pane windows, (3) an inefficient fireplace with no steel stove, (4) a big, cavernous room with high, un-insulated ceilings on one half of the house.

Obviously we could spend a zillion dollars to insulate everything and fix all of the problems I identified above (and probably more), but what is critical?

One thing we started with is putting a thermal curtain between the big, drafty room and the rest of the house so that the thermometer doesn't get triggered by the big room sucking the hot air out of the rest of the house.

1. I would start by lowering the ceiling and insulating it. For ceiling if you insulate it using mineral wool, or glass wool... the vapor barrier [0] is critical and must be placed continuously on the warm part. Also this membrane (preferably containing aluminum so that you get back some of the heat) must be glued to the walls using special glue [1]

2. I would change the windows, with at least triple pane. The windows must be mounted correctly (see RAL montage) and also must be placed aligned with the outside face of the wall.

3. I would take out the floor, and do hydronic underfloor heating with EPS150 or XPS as insulation substrate.

[0] https://www.rothoblaas.com/products/airtightness-and-waterpr...

[1] https://www.rothoblaas.com/products/airtightness-and-waterpr...

Thank you!

what price do you think we're looking at for each of these? lowering the ceiling is a bit of a bummer from a looks perspective. underfloor heating sounds wonderful.

You're welcome! I live in Europe (Romania) and to be honest I would not know what to expect in terms of costs. You lose at least 25% of your energy trough the roof, this can even go up to 30-35% if the ceiling is cracked or air is able to circulate freely trough it.

The bigger the room, the higher the ceiling has to be to feel comfortable. I'd still insulate the ceiling of the big room, but I wouldn't necessarily lower it. Instead, put in a ceiling fan so that the air doesn't stratify. Fireplace isn't critical unless you're actually using it for heating.

Some guidelines for better, healthier, low energy, low cost house construction:

Understand basic physics.

Avoid the architecture-of-the-week construction trends.

Set your targets: Size vs cost? How long do you expect to live there? Price of energy vs better insulation? Maintenance: type, frequency, amount, cost? How important is it for you to reduce the environmental impact? Start small and expand later, or start big and later rent out part of the house?

Stay open minded about the solutions and designs. This makes a huge difference. The building codes and municipal restrictions are often the most limiting factors on how "good" a house you can build. Don't add _unnecessary_ restrictions on top of that. Look around at different solutions, not just what the local construction companies offer. Travel and see how things are solved in other countries.

Use simple construction methods and design. Reduce the number of construction tasks necessary, and make each task simple. A significant real world problem with normal passivhaus construction is that while designed well, they are often very complex to actually build, and small mistakes by the construction crew can have a large impact on the energy requirements as well as cause health hazards.

Well insulated windows, walls, floor and ceiling also drastically improve the comfort feeling of the house, not just the energy bill. When done right and coupled with properly designed ventilation they also improve the health aspects of the indoor environment.

Many low energy houses built today require that the indoor air is kept very dry when the temperature difference between inside and outside increases. This has a lot of negative health effects. By choosing different insulation and interior materials they can be made to allow high indoor humidity. Your lungs, throat, nose, eyes and skin will thank you. Internal humidity around 50-60% also reduces air transmission of many viruses.

Thermal mass is mentioned in some other posts here. Make sure to place it inside the insulation layer, not on the outside. Water and stone have similar high volumetric specific heat capacity. By using water circuits and storage, the mass can be moved out of the way, and often coupled to very efficient heating/cooling systems.

We have developed a construction toolbox for houses and industrial buildings with very low total life cycle CO2 footprint, suitable for climates down to around 0C annual average temperature (northern Scandinavia, around the polar circle). They are fast and cheap to build and provide superb internal environment. If you're interested in more info I'm happy to share. You can ping us at StoneWoodGreyBeard at gmail.

My favorite approach remains the Dome of Visions - https://www.youtube.com/watch?v=1Bn2o-xyS6M

Cool project and name. Ive always been curious if domes like this become problematic in hot weather though or if they have some dynamic that makes them beneficial then too. Not sure how to google that but maybe someone knows.

You mean like Earthships, a modern idea decades old? https://www.earthshipglobal.com/

What I like about Earthships is they attempt a wholistic answer to the gnarly nexus of housing access, resource use, and self-sufficiency, and do it in a simple, beautiful way.

The ideas and methods already exist; we don't need architect-designed glass/steel boxes or exotic manufacturing techniques and materials.

Last year I rented a reformed old fabric and I cannot be more happy with. The building is really well done now and it's energy efficent. I usually turn on the heat for a couple of minutes and the flat stays warn for hours. The windows are really good not only to keep the heat but also letting light in and blocking 95% of the sounds.

They should also look at the Skytherm Roof which can both heat and cool a building passively. See

https://www.architectmagazine.com/technology/harold-hay-skyt...

I don't see anything about heating a building?

It’s vaguely in the article. Says in the winter the process is reversed

I watched a report on a block of "passive houses" in Germany and the people liked it, but had a complaint that the air is too dry, so they dried their laundry indoors. I'm a fan of the idea, so not really critical, but I wonder what it's really like to live in one.

Modern heat exchangers allow you to set the air humidity.

Indoor plants are also useful in this regard, as the plants (and their containers) will return humidity to the air.

Instead of a heat recovery ventilation you can use energy recovery ventilation which gets back some of the humidity, otherwise just buy a cheap electric boiling humidifier and it you get the job done. What is important that in the coldest part of the winter you can turn down the ventilation to a minimal, something like 0.3 hourly exchanges per hour.

> winter you can turn down the ventilation to a minimal

The problem is that the Heat exchanger actively draws moisture out, as it has a huge cold surface area that forces water out of the air. If you don't change the air it feels stuffy.

You can buy heat exchangers with very high efficiency and good moisture reclamation or suppression for a slightly higher cost. The problem is usually that the customer does not look into the details and the construction company can increase profits by buying cheaper versions.

A good modern ventilation energy exchange unit for a 300m2 house can be <30dB, >90% efficiency, and return a lot of humidity.

Yes, the ventilation system inside a passive house needs not only a heat exchanger, but a humidifier as well. Actually, I'd rather dry my laundry to humidify the room than rely on a humidifier that can grow bacteria and mold inside.

> [...] than rely on a humidifier that can grow bacteria and mold inside.

That's down to maintenance and care; change the filters and clean it regularly. Like everything else in your house. You need to change and maintain filters in a heat exchanger as well.

>>than rely on a humidifier that can grow bacteria and mold inside.

There are humidifiers with UV-C lamps inside that sterilize themselves as they run. Dyson makes some, but I've seen them from other brands too.

If you are interested in this, you may like The Zen Of Passive Solar Heating: http://www.iedu.com/Solar/Panels/ which is one of my favourite online project logs.

TLDR:

point one:

you need insulation _everywhere_, along with some thermal mass to make sure there is some inertia to keep temperature even. This means that putting a jacket around the outside of a brick/cement structure is generally better than putting it inside. You need to insulate under the floor.

External wall insulation is not overly expensive. Its about 50% more expensive than a standard silicon render (in the UK)

Point Two:

Windows and doors are normally the weak spot. Standard double glazing has a U value of about 2. Depending on the coating and the position, they can also let in up to 2kw/m2 of heat through solar gain.

You need ideally coated triple glazing, which if paired with the correct frames has a U value of about 0.8-1.1 The coating is to reflect solar gain. You will need sun shading so that in winter the sun comes streaming in, but in summer its shaded out by the small shades.

In the UK its possible to get triple glazing at about the same price as double. For us, the big companies quoted >15k for shitty double glazing, local company was ~10k, eventual installation price was 8k for triple. This included custom arched door/window, and a french door.

> Windows and doors are normally the weak spot. Standard double glazing has a U value of about 2. Depending on the coating and the position, they can also let in up to 2kw/m2 of heat through solar gain.

Also do be careful of thermal bridges and missing seals at and around the frame.

My current rental is relatively well insulated all in all, but one of the huge weakpoints is the stone sill of one of the east-facing windows, I don’t know what the builders fucked up but in winter it can literally serve as a fridge.

> Standard double glazing

How is the code still allowing new construction with windows having U of 2 (such as double glazing)? A more restrictive code would reduce a country's CO2 footprint, companies would sell more expensive products like windows, and no one except the few constructing new homes would be economically impacted - and obviously only short term, while the economic gains are reaped by everyone. So how is this not politically easy to just...do?

> How is the code still allowing new construction with windows having U of 2 (such as double glazing)

its complex. but as I'm retrofitting the rules are different. The standards are here: https://great-home.co.uk/building-regulations-current-u-valu...

But the real kicker is that glazing should have bleeder vents in them, in some circumstances. Which is a pain in the arse. Most of my windows don't have them, but the two in the loft extension do.

Yeah having different rules for retrofitting is understandable (Although it would be good if those who retrofit were at least required to improve the status quo of the building, if not required to bring up to the standard of new building).

But what blocks the code from saying e.g. U=1.2 for new construction which is a normal (and honestly pretty cheap) triple glass window?

Effectively it isn't allowed since the whole building has to meet a minimum efficiency standard which would be impossible to meet with U=2 windows throughout.

My double glazed windows have a U value of 1.2 and typical for triple is 0.8 so the improvement isn't that big between good new double glazed and triple.

The English have been building homes with virtually no heating since forever

I met the founder(s) of ArchiPro at a cloud event in Wellington in either 2013 or 2014 - it is wonderful to see their idea not only be sustained but thrive, bravo!

Milot and Britt's vision for having an impact on the building industry is going to take a lot of work, but they're one of the few people that seem to have unlimited drive for it. - I worked as a dev for ArchiPro from March 20 - December 21

In Oregon the new building code mandates that all air ducts and air handlers be located in conditioned space. Really good common sense regulation imho.

If you have a large enough plot, consider building a home out of jumbo straw bales. Super insulating, easy and fast to build, cheap and eco.

I'd love to see them try this in Sweden :)

Fairbanks, AK:

https://yewtu.be/watch?v=Xen_VWyDezY

There are plenty of passive houses in Sweden.

They are quite different in construction though. The insulation on this house corresponds to a garage in the nordics today, or how the building code looked in the 1970s and 1980s. Today the code requires twice this much insulation for a normal home (around 300mm), and it's still nowhere near a passive one.

One well known example of modern efficient houses is the one Amory Lovins built in the Rocky Mountains in the US. It gets quite cold there, yet he likes to point out he grows bananas in the house.

Can confirm, I visited RMI in the early 2000s.

The entire structure is built with the climate and site in mind. Large south-facing windows, thermal mass in the floor and walls. At the time, the major energy draw was laserprinters, given that the xerographic process used relies on a heating element kept at about 400F. Switching to inkjet printers was a major energy gain (though ink costs might make this a financial wash).

Come to Lithuania (we have winters of -25C and summers of 35C). All new homes have to be build to a building code that actually exceeds Passive House in some cases. In our apartment (built 2016) we don't even turn on the heating until it gets close to 0c outside.

First one was built 20 years ago but getting more popular after 2010. You can order them, it's a building standard so does not require anything from you except money. But they say it's not that much more expensive than a normal swedish house since we already have a lot of isolation and 3 glass windows as standard for the climate.

So what is the difference and why does my modern Swedish house, with heat recovery ventilation and east-south facing windows consumes more energy to heat?

More than what?

Two years ago I spent a week in a passive house near Piteå. The outside temperature was -25c and heating the house was done exclusively using an accumulation tank of solar heated water (yes. It worked just fine in -25 if the sun was shining for more than 2 hour a day).

The only problem was that it got too hot when we were making food or running the tumble dryer.

Heating for that house was between 500 and 2000 kwh/yr depending on how much the sun was shining.

I've been touting the benefits of Spray Foam Insulation for years. It is actually incredible how much money you can save on HVAC every year. Your Heating and Cooling equipment can be halved in size and your living space is draft free and incredibly comfortable. Mate this with geothermal and your utility bills to heat and cool are equivalent to someones Starbucks habit (maybe less). If the North American building code was upgraded to a decent performance level (spray foam, triple pane windows, etc), we could probably get away with not having to build another power plant for decades.

Spray foam is very expensive and is not sustainable. Mineral wool/rockwool is also fairly popular but pricey as well.

Also, it's not just adding insulation. Air tightness is hard problem to address for existing houses.

Spray foam pays for itself, so it's basically free in the long run. Interesting enough people don't bat an eye when someone quotes them 20-30 k for a new Kitchen but if you quote someone 20-30 k to insulate their entire house they look at you like you killed their mother and sister.

The average home has 2000 ft of linear cracks. Everything from poorly sealed doors, windows, and envelope. It's like the equivalent of keeping your front and back door open all year around. So even after spray foaming there is some leakage (blown door test).

Really, Spray foam isn't that expensive, you should be paying about $3 -$4 a sq/ft at around a R-21 which is cheaper than most tile or carpet installations.

https://huntsmanbuildingsolutions.com/en-US/

If I were building a house I would probably go with ICF forms all the way up and Spray Foam the attic and basement floor (under the concrete floor). If I were renovating, I would Spray Foam and try to make the job large enough to cover the contractors minimum charge. Even a couple of rooms can really help the utility bills.

Double stud construction with blown in cellulose is much cheaper than spray foam, and way better for the environment.

Also, if you want close to passive house, you'll need way more than R-21. I would say only use spray foam if your wall cavity is limited and you need the maximum R value.

Double stud construction cheaper? Maybe a while back...

Spray Foam although rated at R-21 preforms much higher since it seals. Blown in Cellulose settles, attracts dust, rodent nesting, and doesn't seal and isn't a vapor barrier or water proof. You get what you pay for I guess.

We have a house in Northern Ontario that is around 4000 Sq/Ft (entirely spray foamed). The costs to heat and cool it are 1/3 compared to the house 2800 sq/ft house in Toronto (insulated with Fiber Glass, Attic Cellulose).

The biggest hurdle is folks just don't give a fuck about the mechanical part of the house. Dry wall covers it all up. What's important is the finish that you see everyday.

Reply on news.ycombinator.com