okay this is driving me nuts, whenever I turn on the heat or the ac or just recirculate the air, my house ends up smelling musty/moldy. At first it was only occasionally, and then it was only when I started it up after awhile of not being on, and then it seemed like it was only coming from a few vents, but now it is all the time, every one. I did have a cleaning/inspection and they said everything looked fine and that that was normal for when you first turn on the AC at the start of the summer season, but I kept telling the guy it was smelling with the heat and that I had been running the AC at max for weeks by the time he came so that was not it, but he just couldn't explain it, just kept saying the same thing, urgh! I keep searching and all I find is that same idea... the musty moldy smell the first couple of days when you first start up the AC for the season, I can't seem to find anything about why it's all the time and even just with having the fan on, doesn't matter if it's heat/ac or neither. Any ideas? I can't stand the smell, it makes me ill. All our duct work is in the roof... I can't find anything looking around in the 'attic' that is at all obvious to me. I'm just at a loss and all the more frustrated that I couldn't even get an answer having someone here...???