Just wanted to let you know we have had our attic fan for over 7 years, and love it!  We use it to air out the house when the weather is warm enough (no mater what season), and it not only makes the whole house smell fresh, but it gets rid of all those horrible cold/flu germs.  It also makes sleeping wonderful on those hot summer evening nights!  We use it much more than our AC unit.
Sincerely,
K.C. and Donna S