「黃家駒 Wong Ka Kui」 | (aka: 鳳凰院 凶真 Hououin Kyouma)How often are your windows open? What about during Winter? or during Summer? Do you open windows to let in fresh air?
JayCanada here. Winter never, unless we have a rare warm (above -10c/14f) day. Spring as often as I can if/when it’s nice enough outside. Summer usually open until the temps get around 27c/80f then closed and the air conditioner on.
I live in a roughly 100 yr old house though, so with all the cracks etc this place tends to self-ventilate anyway.