Comment by throw0101a | Hacker News Reader

Comment by throw0101a | Hacker News Reader

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> The new houses are designed with zero consideration about ventilation, designers seem to take for granted that you are going to buy an AC system.

These are two separate problems.

In the ideal situation, you generally want the house to be fairly air tight and condition the air for (a) temperature and (b) humidity. Each of (a) and (b) are taken care of by different mechanical units: one is monitored by a thermometer and the other by an hygrometer. The latter triggers a stand alone dehumidifier:

* https://www.aprilaire.com/whole-house-products/dehumidifiers

For fresh air you have an HRV/ERV, which brings outside air (through a filter) into the house (usually to bedrooms), while at the same time blowing out stale inside air (usually taken from bathrooms and the kitchen), with the two moving through the unit so that the outgoing air tempers the incoming air:

* https://www.ecohome.net/guides/2276/choosing-between-an-hrv-...

You still have opening windows, as they're mandated for emergency fire exits.

This is exactly the problem with newer design and construction philosophy. Its premise is that we will use mechanical systems, and then try to make these mechanical systems more efficient such as improving insulation, using multi-stage condensers for the AC, etc. This is epitomized in the passive house concept.

In contrast the older philosophy is that natural ventilation is good enough, so we design houses to improve that, such as strategic placement of windows to allow cross ventilation, use high ceilings to allow heat to rise, etc.

The original article is squarely in the second camp.

Indeed. Speaking about hot and sunny cities like mine, besides strategic placement of windows I would also mention barriers to direct sunlight over the walls. Simple barriers can improve inner temperatures sensibily and costs no energy, but most projects don't take that in consideration.

Jesus, here there are even buildings importing those "glass wall" concepts, which makes total sense in climates like European's and north American's, but makes absolutely no sense in sunny cities -- you just end up aggravating the greenhouse effect and having to rely more heavily on AC. Everything because of façade aesthetics.

It doesn’t even make sense in North America - the glass walls make it very unpleasant in summer, even in heavily air conditioned buildings, even in moderate climates (California). It’s like working out next to a space heater, with an AC unit blowing on your neck.

> In contrast the older philosophy is that natural ventilation is good enough, so we design houses to improve that, such as strategic placement of windows to allow cross ventilation, use high ceilings to allow heat to rise, etc.

Yeah, and all those open windows bring in pollen and dust. Yay! Hope you have a good bug screen as well.

Of course if there's high humidity then all than ventilation may not help because the air is already saturated so your sweat doesn't evaporate so you're not cooled.

Natural ventilation could be great if the conditions outside are exactly what you want them inside as well. But if the outside is too hot or too cold or too humid then what are you going to do then?

Build Tight, Ventilate Right:

* https://www.energy.gov/indianenergy/articles/build-tight-ven...

A 5000 sq. ft. / 500 sq. m. house can be conditioned with as little as 2000W (a hair dryer):

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

People lived before 1902 and the invention of compressor-based air conditioning.

Not in all the places and densities that they do today.

People also died a lot back then.

Even today heatwaves in Europe kill a lot of elderly as air conditioning in homes isn't common

People lived before 1945 and the wide availability of penicillin/antibiotics. A lot more folks died from infection as well.

Modern (post energy crisis) houses have 10-100x higher indoor air pollution than the outdoor air. CO2 concentration is also an issue.

Older houses didn't have those issues, but energy consumption and humidity regulation were nightmares.

Removing drafts created and solved many difficult engineering problems.

I think having a tightly sealed house with lots of openable windows is a good solution. Most days, you can hopefully leave the windows open during the day and/or night. On smoky/hot/cold days you can run filters and ac/heat.

In some countries, it's common to open all the windows for 15-30 minutes, even on really cold/hot days. There's basically no thermal mass in the air (vs. the contents of the house), so it uses much less energy than you'd expect, and the house returns to temperature quickly. However, it greatly reduces indoor air pollution (by roughly an order of magnitude), including dust and pollen.

You could get a similar effect with an air exchanger, especially in Alaska, like in your link.

However, those don't usually do much to help with humidity entering/exiting the house, which is the main drawback of opening the windows for 15 minutes.

2000W sounds like a small amount of energy until you realize modern heat pumps have coefficients of power between 5 and 10. So, that house could leak 10-20KW of energy on average, and still meet the 2000 watt goal. (Assuming they installed a heat pump, which they should have before paying for ultra high end insulation.)

Heating and insulation need to be a system. You can't install the heat pump first as it needs to be sized to fit the energy loss of the house.

> Most days, you can hopefully leave the windows open during the day and/or night. On smoky/hot/cold days you can run filters and ac/heat.

I'm in Toronto, Canada: our winters are -10C and our summers are hot-humid 30C.

* https://en.wikipedia.org/wiki/Toronto#Climate

Leaving windows open is not the preferred option for most of the year (though I grew up in a house with A/C, and only first experienced an abode with in in my 20s).

Further, more places are getting bouts of extreme weather:

* https://en.wikipedia.org/wiki/2003_European_heat_wave

My personal preference is deeply in the natural ventilation camp, and the typically delicious air we have in the Bay Area is a boon to my wellness. I leave the windows mostly open 24/7 three seasons, and in the winter I partially open them during significant portions of the day. It’s wonderful.

But during the worsening wildfires seasons, I must tightly seal and air purify my apartment for weeks straight, and had to buy an air conditioner that I run during the day. The stale air is unpleasant, but unavoidable.

How idiosyncratic are my preferences and environmental circumstances? Are any architects working on house designs for me?

> How idiosyncratic are my preferences and environmental circumstances? Are any architects working on house designs for me?

You must have quiet neighbors if you can stand leaving the windows open all the time.

I live in a mid density city with a nice ambient hum. Indeed the neighbors in my building are respectful, as are the neighbors on either side. But I think the ambient hum is key to the peaceful atmosphere, when living in a city. The biggest threat we’ve experienced in terms of noise is blue jays that I finally staved off after months, by occasionally assaulting them with a super soaker. Other birdsong is pleasant, I hear some right now and open the window wider.

I say this as somebody fairly particular about my comfort. I can’t stand interior transformer hums for example.

Respectful neighbors in the Bay Area?

Which city?

The best neighborhood in Oakland (which I will not name).

I think a passive house design would be excellent for you.

Highly insulated, air tight (but vapor permeable) building envelope. Constant intake of fresh air to bedrooms living rooms, filtered and passed through a heat exchanger to heat or cool it with air exhausted from kitchen and bathrooms.

They generally cost about ~25% more than a standard code-built house (unless you want a lot of windows), but cost much less to heat and cool. They're also more comfortable and have less pollen, dust, and even insects.

I think your preferences make total sense. Though I have little experience with wildfires. Would an air filter help?

For my own eccentricities, I have the bedroom window open slightly while sleeping, closed when awake.

During the winter, when inside I wrap up in warm clothes, thermals, scarf. When exercising outside I wear only one or two layers. I call it the 'Winter Paradox'.

> How idiosyncratic are my preferences and environmental circumstances? Are any architects working on house designs for me?

Very. SFO is is in climate zone 3, and the Bay Area is a micro-climate unto itself:

* https://basc.pnnl.gov/images/iecc-climate-zone-map

Do you think Florida or Texas could do the same thing? Minnesota or the Dakotas? Anywhere in Colorado or the New England region?

An architect will design anything you want, as long as it meets code.

> These are two separate problems

I've learned a lot about US climates and their notion of ventilation, here at the comments I got.

I hope you guys also have found interesting that, in some other parts of the globe, ventilation and air cooling are two very interconnected concepts. And also that, in climates like ours, relying solely on AC while not taking advantage of the cooling properties of moving air masses means waste of energy.

Most of western Europe (the part most in Europe reading this are from ) have mild climates compared to the US. Of course the US is a large country, and so there are more climates in discussion. What works well in Europe often doesn't in the US.

Of course one size fits all codes don't help. What works well in Europe will work someplace in the US, just not everywhere

'Traditional' ways may break down in more extreme situations:

* https://en.wikipedia.org/wiki/2003_European_heat_wave

* https://www.bbc.com/news/world-europe-49628275

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