i live in an apartment, 6 rooms wide, (A B C D E F). i live in D. its a 2 story apartment, 3 bedroom. I ALWAYS have at least 3 flies flying around the place, and i kill at least 1 a day. they're mostly on the windows. anyone have any idea why? i think its because of the cold air return vent on the bottom of the wall on 1st floor, goes directly down into the crawlspace. anyone have any other ideas? is it the weather or what?