Best Smart Thermostats of 2021

The top-scoring models from CR's tests are from Braeburn, Ecobee, Google Nest, and Honeywell Home

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A Nest programmable thermostat
The Google Nest Learning Thermostat.
Image: Nest

Tired of high heating or cooling bills? Consider giving your HVAC system an upgrade with a smart thermostat. Most of these high-tech thermostats use algorithms to “learn” your family’s temperature preferences and daily routines, and adjust the temperature for you rather than relying on manual changes or convoluted programming.

But not all smart thermostats are created equal. Our tests show that some models offer far better automation than others, and the most expensive models aren’t necessarily the smartest. Below are the five best smart thermostats from our ratings, listed in alphabetical order. The list has models from Braeburn, Ecobee, Google Nest, and Honeywell Home. CR members can click on each model name to see detailed ratings and reviews.

We also note whether each thermostat comes with a wiring adapter, which allows you to install the thermostat even if you have an older HVAC system that’s missing a C-wire. (Most smart thermostats require a C-wire so that they can receive a constant power source.) For more information on C-wires, plus advice on choosing the right thermostat for your home, see our free thermostat buying guide.

In Consumer Reports’ smart thermostat tests, we evaluate features such as voice control via digital assistants and how easy they are to connect to WiFi. We also assess how easy it is to control them manually from the thermostat itself.

“We find that the best smart thermostats are the ones that use or take advantage of the latest technology, like touch screens and sensors and GPS,” says John Galeotafiore, who manages thermostat testing at CR. “Combining this with a well-designed user interface and the ability to sense and learn by itself is what makes a great smart thermostat.”

For the results on all the smart thermostats we test, see Consumer Reports’ smart thermostat ratings.

Wiring adapter included: No; sold separately for $17 at Amazon.

CR’s take: It might not look like the most cutting-edge piece of hardware, but the Braeburn BlueLink 7320 is a CR Best Buy pick, thanks to its impressive performance and more affordable price. This Braeburn offers plenty of features, too, including a touch screen, vacation scheduling, geofencing (to turn the temperature up or down when you leave and return home), and voice and app control via Amazon Alexa and Google Assistant. It also works with both wired and wireless remote temperature sensors to balance heating and cooling throughout your home. (A wireless sensor is included in the box.) In our tests, the Braeburn receives high scores across the board, including an Excellent rating for automation. Additional wireless temperature sensors range from $66 to $98 and are available at Amazon and Walmart.

Wiring adapter included: Yes.

CR’s take: The Ecobee Smart With Voice Control EB-STATe5-01 blends a simple interface with plenty of bells and whistles for precise programming. The thermostat learns your heating and cooling habits, and adjusts its programming accordingly. It also comes with a wireless remote temperature sensor to place in an area or room that runs hotter or cooler than the area around the thermostat. The thermostat can then either average the temperatures at the sensor and the thermostat itself to heat or cool your home to a uniform temperature, or prioritize the sensor’s temperature over the thermostat’s temperature by using the sensor’s built-in occupancy detection. The thermostat itself also features a built-in occupancy sensor to tell if people are in the room. Other features include vacation scheduling, a touch screen, built-in Amazon Alexa for voice control, and compatibility with Apple HomeKit, Google Assistant, and Samsung SmartThings for app and/or voice control. Ecobee sells additional remote temperature sensors in a two-pack for $80 at Best Buy, Ecobee, and Lowe’s.

Wiring adapter included: No; sold separately for $25 at Amazon, Best Buy, Google, and Walmart.

CR’s take: The Google Nest Learning Thermostat earns one of the top spots in our smart thermostat ratings. It rates Excellent for automating heating and cooling, and offers a wealth of smart features to enhance its functionality, including an occupancy sensor, geofencing, and voice and app control via Amazon Alexa, Google Assistant, and Samsung SmartThings. One caveat: Our testers found that the manual controls aren’t the easiest to use. Google also makes wireless remote Nest Temperature Sensors for the thermostat, which are sold separately for $39 each at Amazon, Best Buy, Google, and Home Depot.

Wiring adapter included: Yes.

CR’s take: Honeywell invented the precursor to the thermostat in 1886. Today, its spun-out home division called Resideo Technologies offers multiple Honeywell Home-branded smart thermostats. The Honeywell Home T5+ is one of the company’s lower-priced models. It’s not as stylish, but the T5+ offers plenty of utility, with a touch screen, vacation scheduling, geofencing (to turn the temperature up or down when you leave and return home), and voice and app control via Amazon Alexa, Apple HomeKit, Google Assistant, and Samsung SmartThings. It also has a hold function that lets you override scheduling, a welcome feature for unusual days like holidays when you might break from your typical routine. In our tests, the T5+ receives an Excellent rating for manual operation and offers great automation to help you save both energy and money.

Wiring adapter included: Yes.

CR’s take: Resideo’s latest smart thermostat is the sleek Honeywell Home T9 RCHT9510WF, which earns an Excellent rating in our test for manual operation and does a great job of automating your heating and cooling. This thermostat comes with a wireless remote temperature sensor for more precise heating and cooling throughout your home and offers a number of other features, including geofencing, a built-in occupancy sensor, a touch screen, vacation scheduling, and voice and app control via Amazon Alexa, Google Assistant, and Samsung SmartThings. Unlike the other Honeywell Home model listed here, the T9 doesn’t work with Apple HomeKit. If that’s a must-have feature for you, consider the other model. Additional temperature sensors cost $40 each or $75 for a two-pack, and are available at Amazon, Best Buy, and Honeywell Home.

For the contractor version of this thermostat that can also control whole-home humidifiers, dehumidifiers, and ventilators, see the similar Honeywell Home T10 Pro THX321WFS. We haven’t tested it, but we expect it to offer identical performance.


Home Content Creator Daniel Wroclawski

Daniel Wroclawski

I'm obsessed with smart home tech and channel my obsession into new stories for Consumer Reports. When I'm not writing about products, I spend time either outside hiking and skiing or up in the air in small airplanes. For my latest obsessions, follow me on Facebook and Twitter (@danwroc).