Your Money MattersConsumer Reports


Consumer Reports: Here's why you should keep your thermostat at 78 degrees

Ideas for staying cool while saving cash
Posted at 8:13 AM, Aug 20, 2019
and last updated 2019-08-20 11:13:02-04

TUCSON, Ariz. - Utility bills typically shoot up in the summer as homeowners crank up their central air 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 more comfortable.

It may take some experimenting to reach a compromise, but 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 whether you care more about keeping cool or keeping your utility bill in check.

Energy Star, a joint federal program run by the DOE and the Environmental Protection Agency, recommends that for optimal cooling and energy efficiency, the coolest you should keep your house is 78° F—and that’s only when you’re at home and awake.

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. 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

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. If you aren’t comfortable at 78° F, lower the temperature a degree at a time and let your system reach the new setting before ratcheting it down further.

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 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. Also, if there’s a heat wave, avoid using your washer, dryer, and dishwasher during the heat of the day. And, 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.