With summer nearing, what's the best temperature to set your thermostat?

Every summer, it is the same thing. The heat rolls in, you turn on the AC, and then your electric bill arrives, and you suddenly question every life choice. If you are a millennial or young adult renting your first apartment or finally owning a home, managing cooling costs is likely one of those adulting tasks no one really prepared you for.

The good news is that some smart, simple habits can make a big difference, and it starts with your thermostat.

The magic number your thermostat should be set at
There actually is an answer to this, and it is 78°F. If you’re home during the summer, the U.S. Department of Energy recommends keeping your thermostat at 78 degrees Fahrenheit for the best balance of comfort and energy efficiency. Yes, it sounds a bit warm, but with a ceiling fan, it feels a lot cooler than the number says.


If you're heading out for the day, work or otherwise, bump it up. To avoid wasting AC, the DOE suggests setting your house to a warmer temperature than normal when you're away.

The secret to saving 10% a year
Here's one of the most underappreciated hacks in home energy management. According to the U.S. Department of Energy’s Energy Saver website on programmable thermostats, you could save up to 10% a year on your heating and cooling bill just by turning your thermostat down 7 to 10 degrees from its normal setting for 8 hours a day. That means raising it in the summer when you’re gone or sleeping.

That's real money, and it only takes a schedule. This can be done automatically with a smart or programmable thermostat, so you don't even have to think about it.

Why this matters more than you might think
You’re not just hurting your wallet when you cool your home, you’re also adding up to a surprisingly large chunk of your total energy use. According to the U.S. Energy Information Administration’s Residential Energy Consumption Survey (RECS), air conditioning made up about 19% of electricity use in U.S. homes in 2020. That’s almost a fifth of your total home electric bill just to keep cool.

For renters and first-time homeowners already juggling student loans, rent, and rising grocery prices, that’s a line item worth paying attention to.

Ceiling fans: use them smarter, not just more
Ceiling fans are underrated, but only if used correctly. Your fan blades should turn anticlockwise in the summer. This forces air downward and creates a wind-chill effect that makes a room feel cooler without actually lowering the temperature.

The problem? Fans are for cooling people, not rooms. If you are not in the room, switch off the fan. Running fans in empty rooms is pointless and a waste of electricity.

Don’t forget your bathroom exhaust fan. Using it in or after a shower pulls out heat and humidity, reducing the load on your AC.

Don't blast it colder, thinking it'll cool faster, it won't
This is one of the biggest thermostat mistakes. If you walk into a 95° F day and set your AC to 65°F, it’s not going to cool your space any faster. Your system will run at the same rate no matter how low you set it. It will just overshoot the temperature you actually want and will cost you more. Set it to where you want it and let it do its job.

Here are a few more ways to keep bills low this summer
These are only small shifts, but they add up over a season:

Keep the sun out during the day. Curtains, blinds and window coverings can significantly reduce heat gain through windows, particularly on the south and west sides.

Keep your AC unit clean. Outdoor units need a minimum of 2 feet of clearance so they can breathe properly. Nothing should be growing on it or leaning against it.

Keep heat sources away from your thermostat. Electronics such as lamps, TVs, or other devices near your thermostat can cause it to think the room is warmer than it actually is, which can make your AC run longer than it should.

Fill the gaps. Weather stripping around doors and caulking around windows keep the cool air you paid for from escaping.

Change to LED light bulbs. They run cooler than incandescent light bulbs, so they put less heat into your rooms and make your AC work less.

Only run full loads. Washing machines and dishwashers give out heat. If you run them only when they’re full, and ideally at night, it takes some of the strain off your cooling system.

Open the windows at night. If it’s cooler outside than in after dark, open your windows and let the cool night air in. Then, in the morning, close everything up to trap the cool air before the day warms up.

The bottom line
You don’t need a new AC unit or a complete overhaul of your home to better deal with your summer electricity bills. Start at 78 degrees when you're home, turn it up when you leave and add in the little habits from there. The savings are real, and they add up over a summer, or a year, or many years of adulting ahead.