A thermostat is the brains behind your home’s heating and cooling system, whether that system consists of a heat pump, furnace, boiler, or central AC. By monitoring and controlling the temperature in each part of your home, a responsive thermostat is key to keeping your home comfortable.

And some thermostats can save you money. A smart thermostat can shave about 8 percent off your home’s heating and cooling bills, amounting to an average savings of $50 a year, according to Energy Star. (Some thermostat manufacturers claim those savings can reach $100 or more.) Of course, non-connected, programmable thermostats—which, according to the Energy Information Administration (PDF) are used in about 42 percent of U.S. homes—can also provide energy savings.

But for years, the problem has been that they’re too difficult to program for many consumers. For that reason, Energy Star stopped certifying the entire product category in 2009. In fact, according to a study (PDF) published in the Energy Research & Social Science journal, 40 percent of programmable thermostat owners don’t use the programming feature to set schedules. That’s a problem because a thermostat can save you money on your energy bill only when it’s set to use less energy. You can do that manually every time you go to bed or leave the house, or program your thermostat to do it for you on a schedule. 

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Enter Smart Thermostats

Smart thermostats, however, are gaining popularity. They tend to have simple controls and touch-screen displays that make programming easier. More important, smart thermostats connect to the internet via WiFi, allowing you to change the temperature at home through an app on your smartphone wherever you happen to be—as easily as you would check your bank account balance. Smart thermostats can also factor in your local weather forecast and "learn" your temperature preferences through sensors and computer algorithms. The idea is to move beyond needing to program the thermostat altogether.

As a result, Energy Star launched a certification specifically for smart thermostats in January 2017. The packaging label makes it easy for you to know which smart models will help lower your energy bills. As of June 2022, 64 smart thermostats have received Energy Star certification, and that number is likely to continue to grow. For top-performing smart thermostats that will save you energy and money, see our guide to the best smart thermostats.

Some of the user interface improvements created for smart thermostats have also trickled down into non-connected, programmable thermostats, making some of them a more easy-to-use option for consumers who don’t want an internet-connected model. In our tests, the top-performing programmable thermostats received ratings of Excellent for ease of programming and Very Good for manually changing the temperature.