As temperatures rise, AC units kick on, and electric bills start to increase, you may be wondering about small solutions for keeping cool and comfortable without cranking the AC. After all, AC is often necessary, but it’s expensive and it uses a lot of energy! Fans use much less energy than air conditioners, and if used correctly, they can make a big difference in warm weather. So let’s get into how to use fans effectively to keep your home cool and comfortable in warmer temperatures.

Check Your Ceiling Fan!

First things first, let’s talk about ceiling fans. Most of us are pretty used to turning these on during the summer already because it feels nice. When you’re using air conditioning to help cool the home, adding in a ceiling fan lets you raise your thermostat setting about 4°F without any difference in comfort. This could add up to big energy savings over the course of the summer!

Hopefully, you’ve been using your ceiling fan all winter to help circulate warm air back down to keep your house cozy, but if you have, you’ll need to change the direction of the rotation. So as the seasons change, take a look at your ceiling fan to make sure it’s moving in the right direction to keep you cool.

Ceiling fans are designed to push the air either up or down depending on the direction it spins. You can change the direction of rotation with a little switch on the base of the fan, or sometimes using a remote with newer models.

In short, here’s what you want each season:

Summer:

Blades should spin counterclockwise as you look up at them, moving air down.

Winter:

Blades should spin clockwise as you look up at them, moving air up.

As to why it matters:

There's a little science to it, and the goal is different depending on the season. In the winter, by using the fan to pull cool air from the ground up towards the ceiling, you can create a convection effect that pushes the warm air that hangs around the ceiling back down to your living space. Heat (or more accurately, warm, less-dense air) rises, so without air circulation, all the warmth from your heating system naturally goes up towards the ceiling, leaving you chilly on the couch. So circulating air in the winter can help your heating system work more efficiently and keep your space feeling a lot cozier.

In the summer, it’s less about the air circulation and more about the wind chill effect. The ceiling fan should be pushing air down towards you because the breeze itself helps to keep you cool. We all know this instinctively—the faster the fan is moving, the stronger the breeze, the cooler you’ll feel. But scientifically, the colder air moving across your body helps transfer heat away from your warmer skin, and the air movement speeds up sweat evaporation (which helps your body cool itself). So you want to make sure your ceiling fans are pushing the air down to get this chilling effect!

Use Window Fans for Natural Ventilation

Especially on days when it’s warm during the day but cooler at night, you may be able to use window fans to help keep your space cool without using AC at all by encouraging natural ventilation. This is where cool air is moved in from the outside by a breeze, clever use of fans, or both!

Window fans can help encourage cross-breeze to take advantage of cooler temperatures outside and save energy. Window fans use a lot less energy than AC, and we all love fresh air in the home!

To help encourage this natural ventilation, first, make sure the window fans are set to push air out. Then, open up some windows or a door on the opposite side of your home. This works best if you place window fans away from the prevailing wind, so that the natural breeze pushes cool air in, and your window fan pushes hot air out. But if you don’t know exactly how the wind moves, just try to create a cross-breeze by opening windows across the space from the fan. And in a multi-level home, use window fans on upper levels to help move rising hot air out of your space.

When Fans Might Make You Hotter

In certain extreme circumstances, especially in very hot and dry conditions, using a fan may make you hotter. Basically, in order for the breeze to actually cool you, the air needs to be cooler than your skin temperature (which in a heat wave could be up to about 100 degrees). The cool air moving across the skin will transfer that heat energy away from you, and it speeds up the evaporation of sweat. But once the air gets hotter than your body, a fan blowing that hot air across your skin is actually heating your skin up faster than if you were sitting in still air. It’s the same reason convection ovens cook things faster than still ovens—moving that hot air across your skin speeds up the transfer of heat, rather than helping you cool down.

There are some variations in exactly when fans stop cooling you down depending on temperature and humidity, but at the most basic, if the air is hotter than about 104°F, fans might not help too much, and they may even make you feel more hot. So in extreme conditions, pair the use of fans with AC units to make sure you stay cool and safe.

As summer approaches, take some time to set fans up properly in your home to help keep things cool without relying only on air conditioning. It’ll help you save money on your electric bills, save energy, and keep the air moving for a fresh, breezy home.