On a sunny day the temperature of an attic can reach as high as 140 degrees! And this high temperature in your attic will keep the indoor temperature higher than the outdoor temperature for several (or more) hours after the sun goes down.
By pulling heat out of your home with the a Whole House Fan, cooler outside air is drawn into the home. The heated air is then pushed out of your home through the attic vents. WHF's can make you more comfortable and could reduce your air conditioning bills.
When you choose a fan, divide that fans cfm by 750 (1 square foot of opening for each 750 cfm (cubic feet per minute) of airflow). This number determines the amount of square footage of net free air required to properly vent. To allow for any restrictions created by screening and louvers multiply that number by 2. This number is the minimum square footage of venting required for the fan to exhaust properly. One can choose a combination of ridge, soffit and/or gable venting to make up the square footage.
