Yes, 0.35 ACH is for the whole house. Most houses do not have active ventilation systems, so that’s all you would get for the bedroom. But that is true that if you are worried about CO2, you should have higher ACH in bedrooms. But this recommendation is not just about CO2, but also things like formaldehyde. Also it is roughly the amount that houses get on average. I have seen studies showing that the cost of sick building syndrome is well worth having higher ventilation rates. So probably more houses should have active ventilation. But if you don’t have active ventilation in a house, I think 0.35 ACH is a reasonable average. Apartment buildings will have active ventilation and higher occupant density, so the ACH will generally be higher, as you point out.
I think it probably depends when your house is built? I would expect older houses to generally be a lot leakier? When I get home and have access to my laptop again, I think I can use the air quality measurements I took, which include CO2, to determine how leaky mine is as an example. I think the way to do this is look at how quickly CO2 levels fall off in an empty room?
While this is an old house, this particular room is essentially new construction: it was gutted in 2017 and redone with foam insulation and new windows, so it’s not surprising that it isn’t very leaky.
Yes, 0.35 ACH is for the whole house. Most houses do not have active ventilation systems, so that’s all you would get for the bedroom. But that is true that if you are worried about CO2, you should have higher ACH in bedrooms. But this recommendation is not just about CO2, but also things like formaldehyde. Also it is roughly the amount that houses get on average. I have seen studies showing that the cost of sick building syndrome is well worth having higher ventilation rates. So probably more houses should have active ventilation. But if you don’t have active ventilation in a house, I think 0.35 ACH is a reasonable average. Apartment buildings will have active ventilation and higher occupant density, so the ACH will generally be higher, as you point out.
I think it probably depends when your house is built? I would expect older houses to generally be a lot leakier? When I get home and have access to my laptop again, I think I can use the air quality measurements I took, which include CO2, to determine how leaky mine is as an example. I think the way to do this is look at how quickly CO2 levels fall off in an empty room?
Looks like the room I’m testing in is only 0.45 ACH / 9 CFM: https://www.lesswrong.com/posts/eMDuTAA9uA7vFKeEA/ceiling-air-purifier?commentId=G6Addw3f7TpLwHCsD
While this is an old house, this particular room is essentially new construction: it was gutted in 2017 and redone with foam insulation and new windows, so it’s not surprising that it isn’t very leaky.