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What makes you think that project is relying on passive solar? In green building that concept has been largely superseded by newer standards like Passive House and Net Zero which generally rely more on air sealing and super-insulation with highly insulated windows.

There is going to be a lot of health fallout though as people start having oxygen depletion from tightly-sealed houses.

It's important that even well sealed homes have both A/C fresh air sources as well as ERV/HRV systems that can recapture the heat/cold the house has while replacing the CO2 with outside air.

ERVs and HRVs are generally part of these designs. Also, nothing stops people from cracking open their windows. The windows are meant to insulate well when closed.

>oxygen depletion

I wish people would stop conflating low oxygen with high CO2.

Even at 5000 ppm CO2 (which "significantly impair" attention, executive function, and risky decision-making[0]), the oxygen has only dropped from 20.95% to 20.45%. This ~2.5% difference is negligible, equivalent to natural variations in atmospheric pressure.

The buildup of CO2 is the issue, not the depletion of O2.

[0] https://www.mdpi.com/2073-4433/13/6/891

Maybe put in some plants?

You'd have to put so many plants in your house that the interior would look like one of those rainforest exhibits at the natural history museum. A couple of houseplants on the windowsill won't even move the needle on CO2 levels in a house occupied by a family.

source?

Don't need a source, it's simple math.

For a plant to absorb 1KG of CO2, it needs to increase in weight by at least ~1Kg.

An average human exhales ~1KG of CO2 a day.

Unless your house plants are gaining half a ton of mass a year, they aren't meaningfully offsetting your CO2 exhilation.

I’m still with you and your point remains, but the plants do release O2 and just retain the C if I recall. Your plants only need to weigh 27% of that at the end of the year, or about 100kg :D

Unless your plants are made out of pure diamond, they also need to gain hydrogen, oxygen, and nitrogen in weight.

But you are part-right, carbon is ~35-50% of a normal plant's weight.

Why ask something that's trivial to google yourself? There are numerous good ones, it's a well-known and noncontroversial topic.

Plants absorb near the same amount of O2 at night as they produce during the day.

Maybe an algae farm is that you'd need.

In addition to concerns relating to carbon dioxide levels, when I contemplate the push for ever-more-tightly-sealed homes and particularly smaller homes with lower ratios of internal air volume to internal surface area (of walls, built-ins like cabinetry, and furniture), the issues stemming from outgassing of volatile organics from the adhesives and sealants as well as from the materials (solid wood became plywood with wood veneering, became sawdust-and-binder with plastic faux-wood veneer, etc.) now composites made of multiple substances and multiple binders and glues.

Some years back, "sick building syndrome" was a prominent topic of discussion and there was a push for fresh air, windows that opened, etc. but this seems to have largely dropped off the radar, afaict.

You are correct that they are viewed as different systems and tend to rely on different strategies:

https://ecokit.us/passive-solar-design-vs-passive-house/#:~:....

To me, it's almost a matter of semantics.

In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unlike active solar heating systems, it does not involve the use of mechanical and electrical devices.[1]

The key to designing a passive solar building is to best take advantage of the local climate performing an accurate site analysis.

https://en.m.wikipedia.org/wiki/Passive_solar_building_desig...

I think of passive solar as the umbrella term for such strategies. My understanding is passive house comes from a German project. It shouldn't surprise anyone that strategies which work well in Germany differ from strategies that work in warmer climates.

There are also traditional building approaches in Middle Eastern deserts that keep the entire city at bearable temperatures. They historically built on a plateau, oriented streets to be cooled by prevailing winds etc.

Both in Mexico and Iran, they have passive air exchange systems that help cool homes. Stairwells in Victorian American homes have similar features and likely served a similar purpose and were probably not merely ostentatious.

If you know a better umbrella term for this approach, I'm open to suggestions.

> My understanding is passive house comes from a German project. It shouldn't surprise anyone that strategies which work well in Germany differ from strategies that work in warmer climates.

It actually started in North America around the time of the oil embargo as a mechanism to reduce energy costs. (See the history section of https://en.m.wikipedia.org/wiki/Passive_house). Once that shock passed, people went back to not caring.

Even at the time, and still today, most write ups are focused on harsh climates like New England or Canada in Winter, because it's harder. It's also the case that in milder climates, the cost to make your home passive has historically been higher than just paying the subsidized bills (and/or requires capital). So most of the US hasn't cared (again) until recently.

Early American "superinsulated houses" (the term-of-art at the time) used 12+ inches of foam, but often forgot about humidity and ventilation. As a result, many early examples became mushroom food.

Modern passive houses use HRV/ERV technology, so they achieve high efficiency while avoiding moisture and mold.

As usual, it's the early adopters that find the problems.

Your own source indicates it was being called passive solar energy design in the 1970s and indicates Passivhaus Institut was founded in Germany in 1996.

https://en.m.wikipedia.org/wiki/Passivhaus-Institut

As someone who has followed such things for decades, it is my personal recollection that this German project is the root source of the expression Passive House. Most passivhaus buildings are in Germany and Austria and everything your source says suggests to me that passivhaus falls firmly under the umbrella term passive solar design.

So I stand by what I said unless someone can find a better source that somehow actually rebuts my understanding that passivhaus is a German project that popularized the term passive house and construction techniques associated with it, but it is simply a subset of the general concept of passive solar energy design.

If you Google “passive solar vs. passivhaus” you will find a lot of results.

This one is the first result which explains the difference in terms: https://www.whitepebbleinteriors.com.au/the-difference-betwe...

I believe passivhaus as a term did originally arise/derive from solar house, but since then the terms have come to mean very different things. I wouldn’t say that solar house is still considered an umbrella term for passivhaus nowadays.

I did exactly that and provided a link to a source in an earlier comment.

I wanted to be a translator at one time. I've had Intro to Linguistics as a college class.

I genuinely have zero problem with people wanting to use the term passive house to refer to a distinct set of building techniques and passive solar to refer to a different set of building techniques. Living languages evolve. It's a known phenomenon.

And, yet, so far no one has suggested to me a better umbrella term than passive solar design.

I defined the term thusly in one of my comments here:

Passive solar design is about creating a home which needs little energy to stay at a comfortable temperature.

My best understanding of life, the universe and everything is that without energy from the sun, earth would be extremely cold. And also wind energy is a form of solar energy which arises from air movement caused by temperature differences.

So to my mind, any technique that tries to keep a home a comfortable temp using sunlight to warm it and air flow to cool it with a minimum of electricity, oil, and other energy sources is using passive solar. It's trying to primarily use energy from the sun in a passive fashion by means of elegant design suited to the local climate conditions.

I guess I need to start defining my terms up front on HN for this topic because I do understand why people want to make this distinction in building techniques, yet I still need an umbrella term for this and I don't currently know of a superior umbrella term to the one I'm currently using.

FWiW and simply as an additional point of interest;

the 1992 second edition of Energy Efficient Australian Housing has an entire chapter entitled Passive design strategies with a section on the use of passive solar energy.

In a sense the entire book is about passive design, optimal placement coupled with sensible insulation to create optimal (and ideally passive (no additional energy inputs)) heat sinks, sources, and flows .. sometimes to heat and sometimes to create a draw and cool as a side effect.

Historically much of this goes back thousands of years to designs that draw in water from a height and use heat towers to create flows through water sprayed gardens, etc.

Regarding passive solar, I liked this video on the Schweikher House built during the 1930s: https://www.youtube.com/watch?v=Qq-3cZ0cbws

I followed you up to the end when you say cities didn't always have more services than small towns and that life in a city wasn't that bad if you were poor. If I think of industrial era first bigger cities, this doesn't seem true? It was way bigger gap between rich and poor quality of life and I'm pretty sure cities always had more services, that's what makes them cities.

I can see why you read it that way, but that's not the point I was trying to make.

These days, a lot of small towns don't even have a full-service grocery store and many people who want to live in a small town have to commute a long ways to get basic essential food they need.

Historically, they may also not have had a full-service grocery store, but a lot more people lived and/or worked on farms and a lot more food was sold locally, not far from where it was grown.

There are essential services that have been unraveling in recent years, making it really challenging to baseline survive in a small town in a way that wasn't always true. And it should not be true that you have a gun to your head to own a car in order to have any hope of having an adequate diet. That's just seriously problematic for individuals and even potentially threatens welfare or survival of the human race.

Something has gone very wrong that it's so hard for so many people to get a decent meal when we are awash in so much societal wealth, yet our systems for how it gets distributed and such have gotten so out of whack.

“ a lot more people lived and/or worked on farms and a lot more food was sold locally, not far from where it was grown”

But they’re not living/working on farms, nor are they living near where the food is grown. Our agriculture system is capable of delivering huge amounts of food for people (including the people who live near fields), but it’s not exactly trying to do that as doing that is not economically efficient.

It doesn't negate your point, but here in the UK, in a village of <1000, mostly elderly people; with a couple of buses a day; nearest market town is several miles away .. people order shopping online, and some suppliers (eg fresh fish, local farm vegetable boxes) bring a van around.

Even in rural areas you can get supermarket home delivery, it costs a few quid for the delivery but is considerably cheaper than car ownership.

Pretty much everyone has cars though.

“when you say cities didn't always have more services than small towns and that life in a city wasn't that bad if you were poor”

Pretty sure they said the exact opposite of that.

“small towns suck because they lack services and big cities suck if you aren't one of the wealthy”

You misread, they were talking about a trend down, which implies it was better before.

Passive solar building design : https://en.wikipedia.org/wiki/Passive_solar_building_design#...

Low-energy house: https://en.wikipedia.org/wiki/Low-energy_house

List of low-energy building techniques: https://en.wikipedia.org/wiki/List_of_low-energy_building_te...

/? Passive solar home (tbm=isch image search) https://www.google.com/search?q=passive+solar+home&tbm=isch

/? Passive solar house: https://youtube.com/results?search_query=passive+solar+house

/? passive solar house: https://www.pinterest.com/search/pins/?q=passive%20solar%20h...

(Edit)

Maximum solar energy is on the equatorial side of the house.

Full-sun plants prefer maximum solar energy.

10ft (3m) underground it's about 75°F (24°C) all year. Geothermal systems leverage this. (Passive) Walipini greenhouses are partially or fully underground or in a hillside, but must also manage groundwater seepage and flooding; e.g. with a DC solar sump pump and/or drainage channels filled with rock.

Passive solar greenhouses (especially in China and now Canada) have a natural or mounded earthen wall thermal mass on one side, and they lower wool blankets over the upside-down wing airfoil -like transparent side at night and when it's too warm (with a ~4HP motor).

TIL an aquarium heater can heat a tank of water working as a thermal mass in a geodesic growing dome; which can be partially-buried or half-walled with preformed hempcrete block.

Round structures are typically more resilient to wind:

Shear stress > Beam shear: https://en.wikipedia.org/wiki/Shear_stress

Deformation (physics) > Strain > Shear strain: https://en.wikipedia.org/wiki/Deformation_(physics)#Shear_st...

GH topic: finite-element-analysis https://github.com/topics/finite-element-analysis

GH topic: structural-analysis: https://github.com/topics/structural-engineering https://github.com/topics/structural-analysis

What open source software is there for passive home design and zero-energy home design?

Round house: https://www.pinterest.com/search/pins/?q=round%20house

The shearing force due to wind on structures with corners (and passive rooflines) causes racking and compromise of structural integrity; round homes apparently fare best in hurricanes.

Walipini passive solar green houses: https://en.wikipedia.org/wiki/Walipini

Earthship passive solar homes: https://en.wikipedia.org/wiki/Earthship

Underground living: https://en.wikipedia.org/wiki/Underground_living

Root cellar passive refrigeration: https://en.wikipedia.org/wiki/Root_cellar

Ground source heat pump (Geothermal heat pump) https://en.wikipedia.org/wiki/Ground_source_heat_pump

Solar-assisted heat pump: https://en.wikipedia.org/wiki/Solar-assisted_heat_pump

(Geothermal Power = Geothermal Electricity) != (Geothermal Heating)

Geothermal power: https://en.wikipedia.org/wiki/Geothermal_power

Geothermal Heating is so old, https://en.wikipedia.org/wiki/Geothermal_heating

...

AC-to-DC (rectifier; GaNprime, GaN) and DC-to-AC (inverter) are inefficient conversions: it wastes electricity as heat.

Residential and Commercial AC electrical systems have a GFCI ground loop (for the ground pin on standard AC adapters)

  WAV: Watts = Amps * Volts

  # USB power specs (DC)
    7.5w = 1.5amp * 5volts  # USB
   15w   = 3a * 5v  # USB-C
  100w   = 5a * 20v # USB-C PD
  240w   = 5a * 48v # USB-C PD 3.1

  # 110v/120v AC: 15amp; Standard  Residential AC in North America: 
  1500w = 15a * 100v  # Microwave oven
  1650w = 15a * 110v
  1440w = 12a * 120v  # AC EV charger

  # 110/120 AC: 20amp 
  2400w = 20a * 120v  # Level 1 EV charger

  # 240v AC plug: Dryer, Oven, Stove, EV
   4800w = 20a * 240v
   7200w = 30a * 240v # Public charging station
   9600w = 40a * 240v # Level 2 EV charget
  14400w = 60a * 240v 

   120000w =  300a *  400v # Supercharger v2
   120kW   =  300a *  400v 
  1000000w = 1000a * 1000v # Megacharger
  1000kW   = 1000a * 1000v
  1MW      = 1000a * 1000v

USB > Power related standards: https://en.wikipedia.org/wiki/USB#Power-related_standards

Charging station > Charging time > charger specs table: https://en.wikipedia.org/wiki/Charging_station#Charging_time

(Trifuel) generators do not have catalytic converters.

Wood stoves must be sufficiently efficient; and can be made so with a catalytic combustor or a returning apparatus (and/or thermoelectrics to convert heat to electricity).

/? Catalytic combustor (wood stove) https://www.google.com/search?q=%22catalytic+combustor%22

Wood-burning stove > Safety and pollution considerations > US pollution control requirements: https://en.wikipedia.org/wiki/Wood-burning_stove#US_pollutio...

Gravitational potential energy is less lossy than CAES Compressed Air Energy Storage is less lossy than thermal salt is less lossy than chemical batteries.

'Pain mound' low tech compost driven water heaters are neat too

For which types of compost is there risk of spontaneous combustion?

What design safety features are necessary for a heat pump to efficiently extract the heat of a wood boiler or a compost pile? Is it safe to locate them next to a heat pump or a dwelling or a thermoelectric boiler?

This is a pile of vaguely relevant facts...

I think in my HN comments I'd prefer a couple of facts and a conclusion, with citations for more detail.

What do you have for low energy, zero energy, passive solar homes?

Buy-all-sell-all says you can't use your solar to power your duct fans even when the grid is down?

Write me a ScholarlyArticle.

It seems unbelievably stupid to me to build solar panel based homes where I live: the northwest US.

Makes a heck of a bunch of sense in CA or TX though.

Passive solar design is about creating a home which needs little energy to stay at a comfortable temperature. It's unrelated to generating electricity via solar power panels.

The northwest US doesn't seem* to be worse than most of the Europe, where we have a veritable boom of solar power. Granted, it produces next to nothing during the winter, but the yearly production makes it profitable still. Even for well insulated house you need some heating in the north, but it can be surprisingly little. It's not like these houses are going to be built totally without network mains.

*: https://globalsolaratlas.info/

Solar is more effective in low temperatures than in high temperatures. Also northwest US is max around 49 degrees north, which is around Paris in Europe and it is normal to have solar much farther north in Europe

Solar panels are extremely popular in Stockholm, 59 degrees North and less than 1,000 km from the Artic Circle. During winter, they produce very little electricity, admitedly... but they work well in all the other seasons so they still significantly reduce electricity consumption.

Europe is warmer than North America due to the Gulf Stream, so during winter at the same latitude, it takes less energy to heat the house.

Anyway, at such lat, it is not possible to survive winter with only solar; you need additional energy source.