An attic fan removes hot air from an attic to prevent it from reaching the house below, while a regular whole house fan draws heat from a home's living area into the attic. Attic fans are mounted to gable walls in the attic.
Attic fans are connected to timers and a power supply, allowing them to run during the hottest times of day. These fans withdraw air as hot as 160 degrees from the attic, allowing air up to 95 degrees from the primary living area to then enter the attic, keeping the whole house cooler. These relatively small fans are significantly cheaper to purchase than standard whole house fans and much easier to install. In fact, many homeowners choose to install this type of fan themselves.
A whole house fan, which is mounted on a ceiling between the attic and living space, is generally located in a hallway in the center of a house where it is best able to remove hot air from the living space. When activated, the fan also draws in cooler air from outside through open windows. Most homeowners leave installation of this type of fan to professionals, as it is a more complicated procedure.