How to better ventilate your home

I started taking IAQ seriously when I soundproofed my home office. The soundproofing made the room nearly airtight, so I had to think about (at the very least) CO2 buildup within the office.<p>I&#x27;ve hit an interesting problem regarding CO2 monitoring: calibration and validation.<p>Every IAQ CO2 meter I&#x27;ve come across allows self-calibration and&#x2F;or calibration by exposure to &quot;open air&quot; which is assumed to be about 400 ppm CO2.<p>But none of the meters provide any means to calibrate &#x2F; validate CO2 levels <i>other than</i> the reference level.<p>For example, suppose I buy two CO2 meters from Amazon. They can both tare to 400 ppm. But once the CO2 in my office builds up, one might read 1200ppm while the other reads 800ppm.<p>According to medical literature, 800 ppm vs. 1200 ppm is a pretty significant difference for human mental performance. If the CO2 level is <i>actually</i> 1200 ppm, I want to crank the office ventilation system, even though it means higher background noise. At just 800 ppm, I may prefer the quiter work environment.<p>Another downside to this difficulty in testing is that it&#x27;s hard to <i>truly</i> evaluate a particular meter&#x27;s performance. Which seriously limits side-by-side comparisons of different models, and makes it harder to hold manufacturers &#x2F; retailers accountable for poor performance.

Surprised to read nothing about the German fascination with Stosslüften (opening as many windows as possible as wide as possible for 5 minutes, twice daily. Literally &quot;shock airing&quot; or &quot;surge airing&quot;).<p>Every apartment I moved into (in Switzerland) had me sign a waiver that I read the instructions how to do this to avoid mold growth.

I’m surprised there’s no mention here of heat recovery ventilators (HRV) or energy recovery ventilators (ERV) here. New buildings are increasingly designed to provide regular air exchange (fresh air replacing indoor air) while retaining thermal energy with these devices, and, in the case of ERV, retaining humidity.

The reason why paperweights exist was because, prior to air conditioning, offices were built to have a constant flow of air through them to cool down workers.

What an odd article. I&#x27;d love to know more about the author&#x27;s background where he&#x27;s just now considering airflow in a home. Maybe it seems strange to me since I was in my late 30&#x27;s before I lived anywhere that had air conditioning, so open windows, fans, cross-drafts, and general air flow were the norm.<p>I also want to see what happens when the author discovers the whole house fan. My very first house had one and it was amazing. Crack open a window in each room and activate the fan. Instant breeze and air circulation in every room with somewhere around 6-8 air changes per hour.

Fun read, my wife sometimes accuses me of having shark DNA because I can obsess over having fresh air moving past me at all times. :-) For me though the difference is one of comfort versus a vague tension. Some folks have associated this sort of thing with claustrophobia as well.<p>That said, we spent a few thousand dollars insulating and sealing our home so that we did not need HVAC assisted climate control. Part of that included finding ways to exchange the house air with outside air so that during the summer months we could pull in cool air at night to lower the house temperature, seal it up when the Sun came up, and then remain cool all day. Similarly with bringing in warmth during the day in winter and minimizing the temperature fall during the evening. This is not particularly great for minimizing COVID in one&#x27;s home.

In the early 20th century, British children&#x27;s educator Charlotte Mason emphasized the importance of air quality, outside air, and frequently changing one&#x27;s inside air:<p>&quot;Unchanged Air.––Parents of pale faced town children, think of these things! The gutter children who feed on the pickings of the streets are better off (and healthier looking) in this one respect than your cherished darlings, because they have more of the first essential of life––air. There is some circulation of air even in the slums of the city, and the child who spends its days in the streets is better supplied with oxygen than he who spends most of his hours in the unchanged air of a spacious apartment. But it is not the air of the streets the children want. It is the delicious life-giving air of the country. The outlay of the children in living is enormously in excess of the outlay of the adult. The endless activity of the child, while it develops muscle, is kept up at the expense of very great waste of tissue. It is the blood which carries material for the reparation of this loss. The child must grow, every part of him, and it is the blood which brings material for the building up new tissues. Again, we know the brain is, out of all proportion to its size, the great consumer of the blood supply, but the brain of the child, what with its eager activity, what with its twofold growth, is insatiable in its demands!&quot; (Charlotte Mason, &quot;Home Education, p. 31. Availible online, <a href="https:&#x2F;&#x2F;www.amblesideonline.org&#x2F;CM&#x2F;vol1complete.html#031" rel="nofollow">https:&#x2F;&#x2F;www.amblesideonline.org&#x2F;CM&#x2F;vol1complete.html#031</a>)

I’ve been looking toward building a new house and it seems the latest and greatest concept is the Passive House which seems to be an incredibly airtight envelope combined with a fresh air system to exchange air that includes a heat recovery system. I am left dumbfounded, as you become completely reliant on this technology which may break down or (more likely) fail to perform to spec or (even more likely) be spec’d incorrectly or incompatibly relative to future uses.<p>It seems to me it would be far better to have large thermal masses and radiant heat, and then allow for the usual air loss around windows and doors and attics. Anyone here have thoughts on this approach vs Passive House?

I recently purchased a home and spent some time improving ventilation in it this year. This is a home in Minneapolis, so just &quot;opening a window&quot; is not an option, as it would be too cold in the winter and dramatically reduce energy efficiency. Its effectiveness also changes based on factors like the wind, and the temperature difference between inside and out.<p>The general strategy for doing this right now with existing homes is to insulate your home as well as possible for energy efficiency, then install a continuous ventilation fan. This is essentially a bathroom fan, except that it runs all the time at a constant low speed, helping to circulate the air through and out your house by &quot;pulling&quot; a designed amount of air through the cracks.<p>I didn&#x27;t want to punch a new hole in the house just to do this, and already had a bathroom fan installed, so as a hack I just turned it into a whole house ventilation fan with this: <a href="https:&#x2F;&#x2F;www.aircycler.com&#x2F;pages&#x2F;smartexhaust" rel="nofollow">https:&#x2F;&#x2F;www.aircycler.com&#x2F;pages&#x2F;smartexhaust</a><p>Basically you calculate how much CFM you need per hour based on the square footage of your house, and then you set it on the fan control. It still acts like a bathroom fan, except every hour it also runs for a set period of time (in my case, about 12 minutes).<p>The standard for this is ASHRAE 62.2. Use this to calculate the CFM for code: <a href="https:&#x2F;&#x2F;homes.lbl.gov&#x2F;ventilate-right&#x2F;step-3-whole-building-ventilation-rate" rel="nofollow">https:&#x2F;&#x2F;homes.lbl.gov&#x2F;ventilate-right&#x2F;step-3-whole-building-...</a><p>Then the formula for calculating the fan run time is on this sheet: <a href="https:&#x2F;&#x2F;cdn.shopify.com&#x2F;s&#x2F;files&#x2F;1&#x2F;0221&#x2F;7316&#x2F;files&#x2F;AC_DOC_7_0_SmartExhaust_Cut_Sheet_rs_20ce4f30-fa23-4dc0-a879-ce2e765fc31b.pdf?v=1593031639" rel="nofollow">https:&#x2F;&#x2F;cdn.shopify.com&#x2F;s&#x2F;files&#x2F;1&#x2F;0221&#x2F;7316&#x2F;files&#x2F;AC_DOC_7_0...</a><p>And presto, you have a ventilation system without having to do a lot of work. Do _not_ try this with a crappy, rusty old bathroom fan - clean or replace the motor first, and for extra credit, use an arc fault circuit interrupter on the breaker so if the motor fails it will blow the fuse instead of potentially causing a fire.<p>Note: This is really just to manage general air quality and VOCs. If you want to specifically make ventilation for COVID-19, that&#x27;s a different problem. They focus on Air Changes per Hour (ACH), and a cubic feet calculation is used rather than square feet. There&#x27;s no &quot;recommended amount&quot; of ACH for managing COVID-19. You&#x27;re likely improving the situation by increasing it, but I wouldn&#x27;t start inviting people over after you did it. ACH is very high in ICUs but staff are still getting sick there.<p>RE Humidity - ideal range varies based on region and outside temperature, but this chart roughly shows it: <a href="https:&#x2F;&#x2F;lh3.googleusercontent.com&#x2F;proxy&#x2F;mPz-jGdLpnPGgvWR3EgfvrhuT5mPgkKK_AQKZNzekzAyvsOGeFvGKK6Jn0kWGPEYYGkEAFM6CE3-BXLQzDEF_7_lV-H6HAfD5bXAl5HvUGB5rAjH9X1fPLLf8Q" rel="nofollow">https:&#x2F;&#x2F;lh3.googleusercontent.com&#x2F;proxy&#x2F;mPz-jGdLpnPGgvWR3Egf...</a><p>I have an on-furnace humidifier controlled by an ecobee for the winter, it&#x27;s a huge quality of life improvement if you live in cold climates, but make sure to set it to &quot;frost control&quot; otherwise it won&#x27;t lower the humidity based on the outside air and you can get mold in your walls. For summer, a standard house A&#x2F;C combined with continuous ventilation should be sufficient to bring down humidity levels.<p>Finally, the &quot;correct&quot; air ventilation is a moving target with trade-offs and concerns of the moment. It was higher in 1925 (30cfm&#x2F;person) to try to prevent tuberculosis and infectious diseases, then was lowered to 5cfm&#x2F;person in the 70s during the energy crisis, and is currently at 15cfm&#x2F;person. I imagine COVID-19 could make us re-consider the current recommendations. <a href="https:&#x2F;&#x2F;homes.lbl.gov&#x2F;ventilate-right&#x2F;ashrae-standard-622" rel="nofollow">https:&#x2F;&#x2F;homes.lbl.gov&#x2F;ventilate-right&#x2F;ashrae-standard-622</a>

I always assumed running air conditioning with windows open was incredibly wasteful. Is this because Japan&#x27;s summers are more temperate than where I&#x27;m used to (Northeast US)?<p>I do find myself sometimes running the AC with windows open when it&#x27;s cooler outside than indoors. For some reason it can be 65 degrees outside but 75 degrees indoors.

Most houses are incredibly leaky&#x2F;drafty (at least in the US), turning on your bathroom fan(s) a few times a day is an easy way to improve ventilation.

Only useful if you live in a climate where the outside air is acceptable for indoors. Since this is from Japan I believe that applies. Where I live the outside temperatures get well below freezing for months at a time so ventilation alone isn&#x27;t useful