Here at Sellair, we receive a number of phone calls with homeowners telling us they use their attic fan to get hot air out of their attic.
Our first question is "why does it matter if your attic is hot?"
Assuming your attic is only used for storage or insulation, the temperature of your attic should not matter. However, the response we receive is "the hot air in the attic makes my house hot, so the fan takes the hot air out of the attic which helps cool my home."
Yes, the attic fan take the hot air out of your attic. The attic fan also takes your nice conditioned air from inside the home and displaces it into the attic. Therefore, you waste energy by using the attic fan - even though it may make you feel more comfortable.
In the picture below, we see the attic fan. The fan, when turned on, takes air from around it to push outside. Since it needs to push air outside and there is only a finite amount of air around it, the fan will actually take air from inside the home and push it outside. This air escapes from all the little creaks and cracks that were not sealed properly.
The solution instead is:
- Do not use an attic fan
- Air seal the home properly to keep the conditioned air inside of the home
- Make sure the attic has proper ventilation in the forms of: soffit, gable, or ridge vents. Vents should be high and low that allow airflow to occur naturally in the attic space
- Now you will be comfortable and energy efficient