Whole House Fan: A whole house fan is a natural cooling device that reduces the need for air conditioning. They can cool the entire house in one hour. Whole house fans can replace decayed air many times in an hour and can even eliminate odors, pet dander, pollutants, and smoke. But these fans run only during the cooler evening, night and morning hours. The purpose of whole house fans is to cool your entire living space, not just the attic. For installing this, extra ventilation might be required. The defect of whole house fans is that they are costly and more difficult to install than attic fans.
Attic Fans: Attic fans reduce the attic heat buildup during the heat of the day. They only aerate the attic space. Attic fans run only during the heat of the day. They actively remove superheated air from the attic. Attic fans dehydrate the air in winter seasons and prevent ice dams while keeping your attic dry. They are cheaper and easy to install but are not energy efficient and don’t cool as well. They work best in cool and dry climates.