Best Setting for Your Central Air Conditioning

Cool ideas for staying comfortable while saving energy

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Smart Thermostat set to 78 degrees Photo: Getty Images

Utility bills typically shoot up this time of year, as homeowners crank up their central air conditioning. To keep costs down, you might try to skimp on the AC—but that can create squabbles in the family over which temperature setting is most comfortable.

It may take some experimenting to reach a compromise. And keep in mind that you’ll save about 3 percent on your utility bill for every degree you raise the set temperature for your central air, according to the Department of Energy.

So what is the best setting for your central AC?

That depends on who you ask—and whether you care more about keeping cool or keeping your utility bill in check. We don’t want to pick sides, but we can give you some guidelines for finding a happy medium.

Both the Department of Energy and Energy Star, a joint federal program run by the DOE and the Environmental Protection Agency, recommend that for optimal cooling and energy efficiency, you find a temperature at which you’re comfortable when you’re at home and awake. Once your family agrees on a thermostat setting, Energy Star suggests increasing the temperature setting by 4° F when you’re asleep and 7° F when no one is home.

More on Air Conditioners

A smart or programmable thermostat makes it easy to match your cooling needs to your schedule, but you can make the adjustments manually if you don’t have one for your central air system. For example, you can try the following settings:
• 78° F when you’re home
• 85° F when you’re at work or away
• 82° F when you’re sleeping

Not everyone finds those temperatures comfortable, as we recently found. According to a nationally representative Consumer Reports survey (PDF) of 2,280 U.S. adults in June 2021, the average temperature that Americans keep their thermostats set to is about 71 degrees during the day and night. The temperature varies a smidge by region, with Americans living in the South reporting that they set their temperatures the highest (72° F during the day and 71° F at night), and those living in the Northeast set it coldest (70° F both day and night).

If you’re more heat-tolerant, you can experiment with the temperature, raising it 1° F at a time to see how it affects your comfort and your budget; 3 percent savings per degree adds up pretty quickly. Do the opposite if you’re less heat tolerant. Try lowering the temperature a degree at a time, and let your system reach the new setting before ratcheting it down further.

Other Ways to Beat the Heat

If you have a fan, turn it on. A ceiling fan or box fan causes a wind chill effect that makes you feel cooler at a higher temperature setting, as long as the humidity isn’t too high.

If you live in an area with moderate temperatures, you might not need your central air conditioning all day and night. Take advantage of cooler night temperatures by keeping your windows open. Close them first thing in the morning, and keep your shades and curtains drawn when it’s sunny outside to prevent the sun from heating up the house.

If you need the AC when you get home, program it to go on before you arrive or, with some thermostats, turn it on with a smartphone app.

If there’s a heat wave, avoid using your washer, dryer, and dishwasher during the heat of the day. Also make sure you use the exhaust fans in your kitchen when you’re cooking or in the bathroom when you’re taking a shower.

Cooking outside on your grill is another way to keep the heat out of the house.

What to Do if You Have a Window AC

If you don’t have central air and depend on window air conditioners, it’s more difficult to keep your home at the perfect temperature. Because the thermostat is in the unit itself, it registers the temperature in that part of the room and might not provide a consistent temperature throughout the space you want to cool, depending on how big and open the room is.

That means getting the right comfort level is more trial and error. Start with a setting that you find comfortable and see how if affects your bill.

If you have a window unit in your bedroom, wait until 30 minutes or so before you go to bed to turn it on so that you’re not spending too much time cooling an empty room.

Thermostats That Help You Save

Using a smart or programmable thermostat is an easy and reliable way to set and keep temperatures that work with your schedule. In our testing, we’ve found that our top-rated programmable thermostats are easier to program compared with earlier models. But if you're interested in automation, remote access, or monitoring from afar, smart thermostats are the way to go.

For the fully automated approach using an app from your smartphone, try one of the smart models featured below. If you prefer not to fiddle with your smartphone to set your thermostat, try a programmable model that you can adjust at home.

CR members can read on for ratings of the top three smart and programmable thermostats from our tests.

Best Smart Thermostats

Best Programmable Thermostats

Mary H.J. Farrell

Knowing that I wanted to be a journalist from a young age, I decided to spiff up my byline by adding the middle initials "H.J." A veteran of online and print journalism, I've worked at People, MSNBC, Ladies’ Home Journal, Good Housekeeping, and an online Consumer Reports wannabe. But the real thing is so much better. Follow me on Twitter.