> I just checked it this morning and I would need to do it around ~15 times a day, additionally a longer 20-40min airing in the morning.
I can't really follow how you checked and were able to come up with these number from apparently one single measurement?
I still think the main issue is that you are not airing properly. The best way is is to create a draft situation by opening windows that are across from each other. If you can open the front door, even better. Again, you need to FULLY open windows, no in between state. Like fully open. If you don't have to remove the plants from the window still, you are doing it wrong. Having windows half-open will do barely anything for air circulation.
If you are not able to sharply drop the CO2 in a few minutes, there might be something else going one that you haven't mentioned. Maybe a HVAC system like another commenter suggested.
> Now if I would be fine with having it constantly roughly between 1000ppm and 1400ppm then I could air it out much less often (because the higher the difference outside/inside is the less volume of fresh air you need to let in to make it drop the same absolute amount).
I mostly use 1.2-1.5k ppm as a signal that it is time to air again. Obviously it is not realistic to never go above 1k ppm and that is fine. Long term exposure might make you slightly sleepy but a few hours of it are probably fine.
So I guess the 15 times would kind of check out if you wanted to keep the CO2 constantly low but that would be indeed excessive.
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.
I can't really follow how you checked and were able to come up with these number from apparently one single measurement?
I still think the main issue is that you are not airing properly. The best way is is to create a draft situation by opening windows that are across from each other. If you can open the front door, even better. Again, you need to FULLY open windows, no in between state. Like fully open. If you don't have to remove the plants from the window still, you are doing it wrong. Having windows half-open will do barely anything for air circulation.
If you are not able to sharply drop the CO2 in a few minutes, there might be something else going one that you haven't mentioned. Maybe a HVAC system like another commenter suggested.
> Now if I would be fine with having it constantly roughly between 1000ppm and 1400ppm then I could air it out much less often (because the higher the difference outside/inside is the less volume of fresh air you need to let in to make it drop the same absolute amount).
I mostly use 1.2-1.5k ppm as a signal that it is time to air again. Obviously it is not realistic to never go above 1k ppm and that is fine. Long term exposure might make you slightly sleepy but a few hours of it are probably fine.
So I guess the 15 times would kind of check out if you wanted to keep the CO2 constantly low but that would be indeed excessive.