If you’re considering getting an attic fan for your home to help you take advantages of the cool air outside during certain times of year and in the mornings and evenings, there’s one thing you need to know: they’re not like they used to be.
Growing up, we had an attic fan left over from a previous generation of occupants of the house. It was huge. There was a big motor in the attic and louvers that took up the entire ceiling of the hallway between the two bedrooms in the house. An ancient timer switch on the wall allowed it to be turned on and set to go off a few hours later.
With this attic fan on and the windows open, there was a great breeze — but since it rarely got cool in the evenings during most of the year, it was just hot air that was being pulled through the house.
Today’s whole house attic fans don’t have those huge louvers anymore. They usually have just one or two openings the size of a skylight. But they still work in the same way. If there’s cool air to pull in, they work well. If there isn’t, they don’t work very well. And they’re still great when you want to clear the hot, stale air from inside your home and replace it the cleaner, drier air outside.
A whole house attic fan is a great alternative to a whole house window fan, which can accomplish the same purpose but must be mounted in and restrict the use of a window.
In either case, you have to also open windows around the house and to make the fan work its best to prevent creating a negative pressure situation that can be unpleasant. With some window fans, this isn’t absolutely necessary, so you have to read up on what you plan to buy before you make your decision.
This much is certain: attic fans aren’t like I remember them as a kid — and that’s a very good thing.