Cooling the Attic
LESLIE: Anthony in Georgia is looking to keep an attic cool. What’s going on at your money pit?
ANTHONY: I was – I built a house last summer …
ANTHONY: … and they installed three little vents at the top. I was in a smaller house; about 1,200-square-foot house. I put a powered attic fan up there; not the gable mount but up at the ridge.
ANTHONY: I mounted it at the top and cut a hole in the roof and put it in there.
TOM: Right, right.
ANTHONY: Seemed to help a lot but I have since been told that you can actually pull cool air out of the house into the attic doing that.
TOM: That’s correct, because what happens is when you turn the attic fan on not only does it depressurize the attic space but it’ll reach down through the walls and through the ceiling, through all the little gaps like where wires run through the walls and that sort of space, and it’ll actually reach in and find its way into the interior space of your house and actually suck out some of the air conditioning.
TOM: So attic fans, even though they do a great job of cooling the attic, unfortunately they don’t stop there and they pull air conditioned air from the house itself.
TOM: So the best way to cool that attic is probably by increasing the amount of ventilation that the builder put in initially. You mentioned three separate vents. It sounds like you have three separate roof vents and what you would want instead is a vent that goes down the entire peak of the roof and that’s called a ridge vent and you want to match that with fully-open soffit vents. Continuous ridge and soffit venting is the best way to flush the warm air out of the attic in the summer and the cooler and moist air out of the attic in the winter when that can cause condensation and mold problems. But not an attic fan.