The drying time is too long - 2-1/2 hr for a regular load of towels. Laundry room is in center of hourse - 2nd fl & runs between the 1st fl ceiling & 2nd fl straight outside. There are water stains on ceiling close to the vent. I've had the vent cleaned & the dryer checked. I've heard a booster fan may help - have called a few places & they have not heard of them. Any suggestions? Thank you.