Both whole house fans and attic fans help homeowners maximize the energy they spend cooling their homes. These two types of cooling devices are often confused with one another, but they serve two distinct purposes. When Montgomery County homeowners are considering installing one, understanding these differences is helpful.

Whole house fans sit in the ceiling and pull hot air out of your home by forcing it into the attic space and out through the roof vents. This process creates negative pressure inside your home, which will draw cool air in through your windows. Most whole house fans will complete 30 to 60 air changes per hour depending on your floor plan and the fan you choose.

This type of cooling option carries several benefits. Some of these include:

  • Provides a natural cooling option: Instead of manufacturing cool air using coolant as an air conditioner would, a whole house fan allows you to use the cool air from outside to cool your home.
  • Brings fresh air into your home: By drawing in the fresh air from outside, a whole house fan makes your entire house more comfortable. By sending stale air out through the attic, it improves the ambiance inside your home.
  • Cools the living space: By removing heat buildup from the entire home, a whole house fan will cool all areas of your house, even those that are sometimes difficult to cool with the air conditioner.
  • Lower energy bills: When you use a whole house fan rather than your air conditioning unit, you save energy.

Whole house fans are best used during the cool of the day, when the outdoor temperatures are more comfortable than the indoor temperatures. They are not used during the heat of the day or on days that are excessively warm, as this would only serve to draw hot air into your home.

By contrast, an attic fan is installed in the roof. Instead of regulating the air inside the house, it regulates the air inside the attic. It pulls hot air out of the attic and vents it into the outside air. When an attic fan is running, the temperature in the living space is largely unaffected.

The main goal of an attic fan is to ventilate the attic space and prevent problems from the attic getting too hot. Because of the way that roofing material absorbs sunlight, attics can often have temperatures as high as 30 degrees over that of the outside air. To help prevent this, an attic fan runs during the hottest part of the day and does not run when the outdoor temperature drops. This is the opposite of a whole house fan.

Attic fans carry several benefits. These include:

  • Controls heat buildup in the attic: By keeping the temperature in the attic close to a comfortable point, your home’s entire HVAC system will run more efficiently.
  • Active removal of super-heated air: Typically, vents allow the super-heated attic air to be removed passively, but the attic fan does this actively.
  • Provides cooling during the hottest part of the day: When the outdoor temperatures soar, temperatures inside the attic can get dangerously hot quite quickly. Attic fans help prevent this.

Because attic fans pull hot air out of attics and bring in cooler air from the outside, homeowners need to be certain that vents are not blocked. Also, they need to ensure that the air conditioning ductwork is well sealed from the attic. This prevents the air conditioning from working harder to cool the attic as well as the home, which will greatly reduce its efficiency.

When adding an attic fan, you will need to add attic vents. The Department of Energy recommends two to four times the normal area of attic vents. This is roughly one square foot of vent space per 750 cubic feet per minute of fan capacity.

If you are interested in benefiting from a whole house fan or an attic fan, Conroe Air’s team of qualified heating and cooling professionals is ready to help. As the largest full-service contractor in Montgomery County, we have the knowledge and materials to do the job well. Give Conroe Air a call to discuss your heating and cooling needs so you can maximize the options at your disposal to keep your home cool.