Is There Supposed to Be a Fan in the Attic to Suck out the Hot Air?

How Fans Work

• Attic fans work by blowing the heated air out through a special vent that only opens when the fan is working. A thermostat triggers the fan when the temperature reaches a certain point. As the hot air flows out, cooler outside air is sucked into the attic through the vents. When the temperature drops below the designated point, the fan shuts off.

Reducing Ultiltiy Bills

• Because the heat from the attic does not enter the home, the air conditioner doesn't have to work as hard or as long, which reduces the overall utility expense and extends the life of the AC unit. The amount of electricity to run the fan is negligible, and there are solar-powered units that cost nothing to run after installation. Since the greatest problem occurs on sunny days, the solar-powered fans are sure to work.

Fan Size

• Determine the size of the fan your home needs by multiplying the square footage of the attic by .07. The resulting number is the cubic foot/minute (CFM) that the fan needs to move. Compare that with the specs listed for a fan to find out if it is powerful enough. A large attic may require multiple fans to move enough air to cool the home.

Whole-house Fan

• A whole house fan is not the same as an attic fan. The whole-house fan sits between the attic and the interior of the home instead of the attic and the outside. The whole-house fan brings air from the entire interior up into the attic where the fan pressure forces it out of the vents, creating a natural breeze throughout the house as the air moves toward the fan. This type of cooling system requires an open floor plan to work.