Homeowners are always looking for ways to keep their homes more comfortable while also reducing energy use and power bills, and one option they sometimes explore are attic fans.

There are, however, both positives and negatives to this solution, and today we’re going to go over a few of these to help you decide if an attic fan is the right cooling solution for your home.

Pro: They Save Energy
The purpose of an attic fan is to vent warm air from the house through the attic and replace it with cooler outside air. The best time to run an attic fan, therefore, is in the evening after the sun sets, and ideally when the temperature outside is below 70 F. Attic fans are more energy-efficient than air conditioners, as they’ll typically use no more than 10 to 15 percent of the power needed to run an air conditioner, making an attic fan a more affordable cooling option.

Con: Attic Fans Don’t Work Well in Conjunction with Air Conditioners
Exterior air generally has moisture in it, and air conditioners combat this humidity in their effort to keep your home cool. Because attic fans are designed to draw in exterior air, this would force an air conditioner to work even harder, which is why these two appliances aren’t designed to work together.

For an attic fan to work most effectively, you open all the windows in your house when the outside temperature gets low enough, and the fan then draws in cooler outside air and pushes out warmer inside air. When you’re running an A/C, you want to keep the windows and doors closed at all times. As such, you either choose an attic fan or an air conditioner, but not both, unless you plan to use them during alternating seasons (for instance, using the attic fan in spring and fall and the A/C in summer).

Pro: Fans Make Your Home More Comfortable
In the right circumstances, attic fans are very effective at keeping homes cool, and that means your home will be more comfortable for less money. As long as you keep your home sealed up throughout the hottest part of the day and then open your windows in the evening and morning to let the fan work its magic, then you’ll be able to keep your home cooler throughout the summer.

Con: Attic Fans Aren’t Always Advisable
Because attic fans rely on cooler temperatures and ideally dry air in the evening, they aren’t effective in all climates, especially if the nighttime temperature doesn’t drop below 80 F where you live. Moreover, if your water heater or furnace is located in the attic, then an attic fan won’t be the best solution for your house. Finally, because attic fans require you to leave your windows open throughout the night, they don’t always make sense in neighborhoods that have security issues.

It’s important to note that there’s a difference between whole-home fans (the topic discussed here today) and powered attic ventilators, which are less effective because they tend to draw air conditioned air into the attic and force your A/C to work harder. In general, as long as you live in a safe neighborhood and have a climate that’s suited to attic fans, then these appliances can be an ideal solution to keep your home more comfortable for less during the warmer months.