Window closed means no flies could ever come in, whereas with an open window it's a possibility. So purely from a statistical point of view...
I've never noticed the number of insects reducing from open orifices, only increase, presumably until it's the same number per m³ as outside (or higher if you have food out, perhaps). I won't rule out that there might exist configurations where flies are more likely to fly out of than in to, but aside from conical shapes designed to do that (i.e. not regular windows), has anyone ever noticed that opening a window reduced the number of insects inside?
I've never noticed the number of insects reducing from open orifices, only increase, presumably until it's the same number per m³ as outside (or higher if you have food out, perhaps). I won't rule out that there might exist configurations where flies are more likely to fly out of than in to, but aside from conical shapes designed to do that (i.e. not regular windows), has anyone ever noticed that opening a window reduced the number of insects inside?