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Comment by goodells | Hacker News Reader

The fan wouldn’t be exchanging fresh air, it would be drawing it up from the ground. Radon gas is a product of decaying uranium underground. It usually gets into homes due to the “stack effect” where heated indoor air rises (in winter) and draws the gas up through the foundation. The parent commenter seems to be proposing a mechanism to do this in summer as well, just using a fan instead.

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You open the windows in the house when running the whole house fan.

When we installed the fan, the documentation mentioned failure to open 9 square feet or more of outside doors/windows could result in a window breaking from the negative pressure.

We have a radon meter in the house. Even just a single box fan in Window, sucking air out of the house makes and ENORMOUS difference. We're talking <1 ppm, whereas before it could get up to ~12ppm on bad days. We bought a radon removal system when we bought the house, it it doesn't seem to work nearly as well as simply venting the house.

Like someone else said, you open the windows.

A negative pressure house is bad for more than just radon. It can cause certain appliances to vent bad stuff into the house too.

Would you eventually suck them dry of bad stuff? Would putting appliances in a negative pressure environment before selling them to consumers be good?

"bad stuff" in this case is combustion gas from natural gas appliances, sewer gas from sucking the water out of toilets, etc. So no, there's no end to the "bad stuff" they generate.

Separately, offgassing is an issue for sofas and mattresses, anything made of particle board as well, but if you put them in a low pressure environment, it doesn't drastically accelerate offgassing. If they offgas formaldehyde, they're going to keep doing it after the low pressure period has ended, so better to avoid those materials altogether.

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