There seems to be a lot of confusion here on what a attic fan and a whole house fan is.
An attic fan draws cooler air in from the soffit vent and exhausts hot air either though a roof vent or gabble vent, and only ventilates the hot air build up in the attic.
A whole house fan is mounted in the ceiling of the upper most level and draws cooler air from the house's windows, exhausts it into the attic and out a gabble vent or roof vents that needs to be sized to the CFM of the whole house fan.
http://www.airscapefans.com/learn-ab...attic-fans.php