I think you fail to realize air flow situations of various apartments can _massively_ differ due to factors fully outside of the control of the people living th

I think you fail to realize air flow situations of various apartments can _massively_ differ due to factors fully outside of the control of the people living there. I had done measurements in the past and just doubled checked if I remembered correctly and how a 55m wait 5m airing cycle would work by doing it for the first 6 or so hours of my day. > I mostly use 1.2-1.5k ppm as a signal that it is time to air again. The think is if I as much as reasonable possible air out my apartment for 5min when it hit 1200ppm it e.g. just now went down to around 1000ppm... And yes the airing situation in my apartment is not optimal, but that is with what I meant a lot of German "common knowledge" and (worse) regulations are often not fully thought through. It's based on the "how it should be" situation and blindly applied instead of how it actually is. And a lot of apartments in Germany have sub-par airing conditions in Germany, including worse then mine.