On average, we inhale 20 lbs of air per day. This is greater by weight than the food or water we consume in a day. We should be paying a lot more attention to air quality.
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We can't even slow down the consumerism. Everyone's job around the world is someway tied into this rampant production of cheap plastic goods to replace cheap plastic goods from yesterweek. You try and nip it in the bud everyone is liable to lose their job and everything might very well collapse because of how we chose to stack this deck of cards on this planet.
We used to burn leaded gasoline in our cars, coal pucks to heat our homes, smoke directly into our lungs on purpose, god knows what else.
I do agree with the broader point though.
You're really left with two good solutions, one is centralized airflow with appropriate HEPA filtering which many can't afford, or to move to a location with default clean air, again a difficult proposition depending on work etc.
Its a shame homes arent built like that anymore. Looking at how houses like this work really shows how we have created solutions to our own problems in modern home building.
Where I grew up on the shores of Lake Michigan average temperatures average between 32C and -6C. As for extremes, I have personally experienced there highs around 37C and lows down to -28C (still went to work in 3ft of snow).
So I will take my modern home with its ability to be well insulated and heated and cooled.
Yes, people lived there long before those modern conveniences, and they were cold and hot. They kept warm in the winter by keeping fires going inside their dwellings at all times. I even spent a week in autumn living in a recreation of one as a kid. Unsutprisingly, it was cold and everything smelled of smoke by the end of the week. Think of how much smoke and particulate we breathed in to stay warm (and there wasn’t even snow on the ground yet). I didn’t even mind it.
I’ll give the final word though to those living in even colder and more extreme climates, and any intrepid people living above the Arctic Circle.
You're right about building materials, but that's true regardless of the air tightness: engineered woods, all kind of glues, all kind of foams, paints, sealants, hard to tell how nasty they are but they for sure aren't beneficial.
The problem is that people want "cheap" houses, cheap houses coupled with modern regulations = sealed boxes. The average joe doesn't give a shit about building quality, it's all about getting something big and as cheap as possible.
This costs power and materials. Old houses dont require that. On a global scale, that increases power and manufacturing on a huge scale. Why are we throwing power and more modern materials at a problem that was solved in Roman times?
This would also reduce cost, helping the 'cheap' houses issue.
There are plenty of systems to do this. My favorite is an ERV, with an aftermarket, oversized, upgraded supply filter.
This stuff is amazing: not only is it safe (no airflow in contact with fiberglass) and fairly well insulated, but it has excellent acoustic insertion loss. If you take 100 feet of rigid galvanized steel duct and talk into one end, someone at the other end will hear you loud and clear. If you take that same duct and install duct liner (and incredibly annoying process) like a fancy commercial installer, you won’t hear much at the other end. If you use 100' of flex duct, you will hear basically nothing. This stuff mostly outperforms even the most expensive commercial acoustic solutions!
Here’s a spec sheet from a random brand:
https://www.flexmasterusa.com/Portals/2/Downloads/Flex/6B.pd...
Wow, 12 feet of 6" duct attenuates 250Hz sound by 43dB! That will make that frequency close to inaudible even if the equipment end of the duct is quite loud as HVAC gear goes. Use wider duct or a longer run (or both) to get it even quieter and to make a bigger dent in the lowest frequencies.
So you stick you fancy fan somewhere that you won’t directly hear it (in mechanical space with a fiber-insulated wall between you and it) and you connect it to the living space with ducting that contains at least a decent length of insulated flexible duct. And you keep the grilles and ducts large enough to keep face velocities low so that the ducts and grilles themselves don’t make much noise, and you have a fantastic system.
Or you use extremely expensive specialized semi-rigid ventilation duct or rigid galvanized steel or uninsulated flexible aluminum, and you’re sad because your duct is a speaking tube.
Having grown up and lived primarily in (uncomfortably!) drafty old houses, I've noticed the phenomenon ever since I was little kid because they have a distinctive stuffiness and smell of furniture/carpet/plywood even if nothing inside is actually new. I think many people are just used to it/consider it a normal smell of a house because so much of the housing stock is in this category.
Most stone makes for a pretty bad insulator. But the ground, in aggregate, is a great insulator and has very very large thermal mass. So you can go in a hole that’s more than a few feet underground, and the temperature is fairly constant.
Really?
A high quality modern balanced ventilator can ventilate an average sized house using 20-40W. That can supply over 100cfm and avoid around 90% of the conditioning that those 100cfm would otherwise require.
A good approximation is that 1 cfm at a 1 degree F temperature difference transfers 1.08 BTU/hr (sigh) or 0.317W of “sensible heat”. So, in a mild Mediterranean climate in the winter, heating by 30 degrees F, that 100cfm needs 0.317 times 3000 = 951W of sensible heat added.
So you can burn 951W of fuel. Or you can use 20-40W to get the same amount of fresh air but only need 95W to heat it. Or live in a climate with warm days and cool nights and require less thermal mass and therefore less material to moderate the temperature and avoid the need for active heating or cooling.
Without an HRV, either you don’t heat the building, or you ventilate less, or you use considerably more resources for temperature control.
Oh, and the device itself is two fans, a heat exchanger (fancy piece of plastic, generally), and some electronics and a box. Not exactly resource-intensive to build. And it can usually completely replace your bathroom fans if configured to do so, making it even less resource intensive.
In climates that require dehumidification or winter humidification, it’s more extreme because an ERV can exchange humidity (“recover latent heat”) too.
Glues are getting better over time. Slightly nasty polyurethanes [0] and quite nasty solvent- and bitumen-based products are gradually being replaced with STPE, and STPE seems to be considered quite safe. It doesn’t even have a prop 65 warning!
[0] Polyurethane may well be harmless when fully cured, but the uncured isocyanates are most definitely nasty. Fortunately, they’re so reactive that they will aggressively react with water (even just moisture in the air) or almost any alcohol and produce much safer products.
Yes
> ventilate an average sized house using 20-40W
Lets take your conservative estimate of 20w
Quote from Googling: "As of July 1, 2023, there were 145,344,636 housing units in the United States"
145,344,636 x 20w = 2906892720W or 2906.89272MW.
Another quick google says that the average Nuclear power plant outputs 977 MW.
So thats 3 whole nuclear power plants required just to power the hrvs in American homes, using your conservative estimate.
That is without the power required to manufacture, transport, and install 145 million hrvs.
However you phrase it and whatever you say to justify it, thats a huge amount of power required to replace something which nature is quite capable of doing itself.
EDIT: I have just also considered the waste as well. The average HRV has a lifespan of 15 years, so that would be 145 million hrv pumps thrown out and new ones built every 15 years. Thats a massive amount of constant power being used, and mountains of unecessary waste, as well as the power to process that waste etc etc...
Put another way, of course you can naturally ventilate a house to get the same air change rate that an HRV/ERV will get you. But (a) if you live somewhere with poor outdoor air quality, you have no opportunity to mitigate it with natural ventilation and (b) natural ventilation at high rates requires far more active heating and cooling in climates that need heating and cooling.
Even just the power needed to operate a large enough standalone air purifier in a naturally ventilated house will be far larger than the power needed to run a filtered ventilation system that will outperform that standalone filter (in a well sealed house or a positive pressure system).
As I write this, I’m running an ERV that is consuming 25W to supply HEPA filtered air at very slight positive pressure. The same ventilation rate, from unfiltered natural ventilation, would remove 500W of heat, and I’d probably need at least 100W of air purifiers running to get anywhere near the level of filtration that those 25W include at no additional cost.
You seem to be trying to tell me that the 25W would scale to a lot of power if everyone did this but that the 500W I would use otherwise would have no impact because the Romans didn’t worry about it. I’m unconvinced.
(This is a system where I replaced the mediocre and undersized filter from the manufacturer with a monstrous 24"x24"x12" nominal HEPA filter, a 24"x24" MERV 8 prefilter, and a carbon filter mat from McMaster-Carr. I expect the HEPA filter to last for several years, the extremely inexpensive prefilter to last for a year or so, and the carbon filter to need replacement more frequently if outdoor odors from wildfires become an issue. Why HEPA instead of a 99.9% filter with somewhat lower resistance? Because it’s much easier to buy a real HEPA filter and the added resistance is negligible. No additional power is consumed by any of this: it all has less resistance to airflow than even a brand new factory filter. The only real downside is that it’s physically large.)
I however will stick with my house which uses zero external grid power to heat or ventilate it, and I can be happy in the knowledge I am not putting any drain on the national power grid for my comfort.
Also when we have power outages, which is quite often, it makes no difference to my home whatsoever.
Its OK, we can agree to disagree. You are not alone in thinking electricity is an infinite resource. Lets just keep on building houses that require more and more power to run and see where that gets us!
Huh? I'm literally explaining, with actual measured numbers, how the ventilation system uses less power. I do care about it!
This is because it seldom rains. So when it does rain the soil is very hard and doesn't absorb much of it. So it comes down the hills and causes landslides and shifting soils in the alluvial valleys that much of californian civilization is built into (since channelized due to said wandering waters destroying early californian civilization multiple times until this was learned and tamed by the u.s. army). And then, of course the earth quakes, which destroyed an early brick structured version of san fransisco almost in its entirety in 1906.
Not to mention available american and canadian lumber connected by railhead to the entire continent. most of such reserves in europe were claimed for sunken ships over the previous centuries. So now you live in a 300 year old stone house probably with a basement instead of a timber building on post and piers because you have no cheap timber to this degree here and you have no earthquake risks or much shifting soil. Could you build a house like yours in the U.S.? Of course, if you pay a premium for it.