When I moved into our recent house, the house inspector was telling me that I should avoid leaving windows open for long periods of time.
Apparently this region has a lot of dust, pollen, and fungal spores that are floating in the air outside.
Leaving windows open for hours or longer invites all of these particles into the house. They settle on surfaces and get into the air that you breathe every hour that you’re home. The house inspector was right, because I still deal with insane amounts of dust and dirt despite leaving our windows shut at all times. It gets into the house whenever I open the front door to walk outside. And when I come back indoors, more of the airborne particulates get in. No matter what, I find a thick layer of dust on the surface whenever I go to upgrade our air conditioner filter. At first I tried to get 3 weeks without replacing the air filter, but now I can barely get by for 1 week without needing to put in a new one. I decided to supplement our central air conditioner with a media air cleaner. I run this machine in our living room and leave it on the floor so it collects the dust and dirt that gets walked into the house from outside. Now the filter in the media air cleaner gets dirty so the a/c filter lasts much longer. That also means there is less contaminant getting into the air conditioner altogether, which will result in cleaner air while the program runs and cycles.