Does it Help to Run a Whole House Fan during a Heat Wave?

Whole house fans are a great way to keep cool without wasting energy and money. People use them as an alternative or supplement to traditional air conditioning, depending on where they live.

If you have a whole house fan or are considering one, you may be wondering if you can use it during a heat wave. Below, we’ll go over how whole house fans can work and how they can help you in a heat wave.

How Do Whole House Fans Work?
Whole house fans are installed on the ceiling below your attic. They pull fresh air through an attic vent and exhaust it through open doors or windows in the home.

When heat builds up inside the home and exceeds outdoor temperatures, whole house fans are very effective at cooling down the house. Plus, they provide a comfortable breeze. For this reason, whole house fans are most commonly used at night and in the early morning when temperatures drop.

So what about when it’s hotter outside than it is indoors like during a heat wave?

Using Your Whole House Fan During a Heat Wave
As we discussed, whole house fans are best used when outdoor temperatures are higher than indoor temperatures. This is because these fans work by exhausting indoor air and replacing it with outside air.

During a heat wave, high pressure causes high temperatures to remain trapped in the area, meaning that the heat often will stick around during the nighttime as well. Therefore, running your whole house fan may seem completely pointless. While your fan may not be as useful during these times, it can still help.

During a heat wave, your attic will likely experience extremely high temperatures. As your attic heats up, it will heat up the rest of your home and make your AC work much harder to cool the house, wasting energy and making it more difficult to be comfortable. By opening up a window at night and running your whole house fan, you can exhaust some of the heat from the attic and help your home cool down for the following day.

Even better, invest in an attic fan, which is made for this express purpose—to actively ventilate the attic and prevent the buildup of heat and moisture. Not only does an unventilated attic make the rest of the house hotter, but it also can cause mold, mildew, rot, and ice dams which can result in costly repairs.

WholeHouseFan.com has been supplying homeowners and contractors across America and Canada with whole house fans since 2001.