How Much Does an Attic Fan Save?

Identification

• Attic fans are installed to cool your attic during hot months with cooler outdoor air from the soffit vents. When air flows through your soffit vents, it pushes the hot air outdoors to help keep your home cooler. Attics that are not ventilated properly will cause cool air from your air conditioned home to enter your attic, which will make the air conditioner work harder and raise your energy costs. Just how much an attic fan will save you on your electric bill each month depends on proper attic ventilation and how well your attic is sealed. The U.S. Department of Energy states the average homeowner will save as much as 20 to 50 percent by installing the appropriate fans for ventilation and sealing all air leaks inside the attic.

Types

• A whole house fan is a permanent fan that is installed in the attic. This fan is designed to remove hot air and replace it with cooler air from the outside. The California Energy Commission recommends running whole house fans when the outdoor temperature drops below 80 degrees and during the early morning hours. Solar attic fans are also available. These fans are fairly easy to install because there are no electrical wires to run throughout your attic. Solar fans are installed in your roof and are powered by built in solar-electric module panels.

Benefits

• Installing an attic fan will decrease the load on your air conditioner, which is an important part of reducing energy costs. When hot air is not expelled from your attic properly, your air condition must work twice as hard to keep your home at a cool, comfortable temperature. You will receive the most benefit from your attic fan if you set your thermostat as high as is comfortable during the summer months and as low as is tolerable in the winter.

Considerations

• Sealing all air leaks inside your attic will also help reduce your energy usage and keep costs low. Caulk all small to medium-sized gaps around pipes, electrical wiring and air ducts. There are often larger gaps near the attic sealing, which can be sealed effectively with foam board insulation. Inspect your attic for signs of moisture damage to reduce mold growth and wood rot. Be sure your attic insulation does not cover or block your soffit vents, which impedes air flow and increases energy consumption.