Will an Attic Fan Make Me More Comfortable?

Will an Attic Fan Cool My Home?

I keep getting this question from our customers in recent months as we are hitting warmer weather. 

The idea is compelling, if your attic is trapping heat due to intense sun, why not try to cool the space with a fan? In practice though it just doesn’t pan out reliably and here is why.

The Science of Air Circulation

Air moves the path of least resistance, in this case when you create a negative pressure inside your attic the air doesn’t just come from outside. Unless your attic is perfectly sealed, there are still many connections to the interior of the home. 

By introducing a fan, we can actually pull cool air from inside the home into the attic, causing your a/c to work harder and defeat the purpose of the fan. In extreme cases where there is insufficient ventilation in the attic to supply air to the attic fan, this can be enough to impact air quality and efficiency of cooling further by drawing air and moisture into the home from the crawl space or other undesired areas.

Why Air Sealing and Insulating Is Better

The right solution is to seal the attic to isolate air movement from the home as best as possible, and then increase the insulation in the attic. Heat also moves the path of least resistance, and modern code levels of R-49 are usually quite sufficient to reduce the discomfort of having a sweltering attic. In the next code cycle we are looking at R-60 in my region, and you would be very hard pressed to see much of a difference in comfort by introducing an attic fan once your home is insulated to that level.

Written by Tacoma’s HomeRx Branch Manager Kyle Chase. To learn more about how we can keep you cool and improve the comfort of your home, call us at 800-723-5588 or request service.