5 top-rated smart thermostats to save energy and money
Is a smart thermostat right for you? Should you invest in a learning smart thermostat? We asked the experts.
If you have a smaller space and don’t need all of the advanced functionality of the Ecobee Premium, the Ecobee3 Lite is a more affordable alternative that offers most of the strengths of the brand, namely wide smart home and remote sensing compatibility.
Compared to the Premium, the Lite does not have built-in voice controls and cannot control other smart devices in your home. The Lite version also does not physically detect whether you are home or not — you have to buy a separate Ecobee remote sensor for that function.
Still, if you live in a smaller space, or don’t have too many other smart devices to control, the Ecobee3 Lite is a great option for many of the same reasons the Premium is. It’s compatible with almost all major smart home hubs, learns your routine as you go, and can be controlled in detail through the Ecobee app.
Works with: Amazon Alexa, Apple HomeKit, Google Home, Samsung SmartThings | Control: On-unit, ecobee mobile app | Remote sensors: Yes (sold separately) | Energy Star Certified: Yes | Installation: C-wire required | Screen size: 4.05 x 1 x 4.05 inches
For a sleeker, set-it-and-forget-it addition to the home, consider the Nest Learning Thermostat, which has a circular glass face in a stainless steel casing and comes in seven colors. Instead of touch controls, you control this thermostat by taping and turning the touch-sensitive outer housing, like you would turn a dial.
For the first week of using the Google Nest Learning Thermostat, you have to control your temperature manually. Once that week is over, the thermostat builds a schedule and routine based on your behavior, and continues to adjust temperature and settings as it learns more from your daily activity. This advanced learning makes it easier to set it and forget it compared to options on the list.
The Google Nest Learning Thermostat has a sensor built-in to detect whether someone is home or not. If you have a bigger space and need more granular control over different parts of your house, it is also compatible with remote sensors (sold separately).
It is compatible with Amazon Alexa, Google Home and Samsung SmartThings. Note that it is not compatible with Apple Homekit.
Works with: Amazon Alexa, Google Home, Samsung SmartThings | Remote sensors: Yes (sold separately) | Control: On-unit, Google Home mobile app | Energy Star Certified: Yes | Installation: C-wire and no C-wire options (C-wire adapter sold separately) | Size: 6.5 x 6.5 x 3 inches
If you want a sleek design but don’t need advanced learning or remote sensors, Google’s Nest Smart Thermostat is much less expensive than its Learning model.
Instead of touch controls, you control this thermostat by tapping and swiping on the tactile touch bar on the right side of the housing. Like the Google Learning Thermostat, you can control temperature, set schedules and more through the Google Home app. Through the app, it will send you notifications, monthly energy usage reports and more.
This thermostat does not have the advanced activity tracking and automatic schedule adjustments present in the Learning model. It does not have a sensor built-in to tell if you are home, and is not compatible with additional remote sensors.
It does have wider compatibility than the Google Nest Learning Thermostat though, as it is able to connect to Apple HomeKit systems through Matter, a new protocol that aims to increase smart devices compatibility.
Works with: Amazon Alexa, Apple HomeKit (via Matter), Google Home, Samsung SmartThings | Control: On-unit, Google Home mobile app | Remote sensors: No | Energy Star Certified: Yes | Installation: C-wire and no C-wire options (C-wire adapter sold separately) | Size: 3.31 x 3.31 x 1.07 inches
The lowest-priced smart thermostat on our list, the Amazon Smart Thermostat is only compatible with Amazon Alexa smart gadgets — Google, Apple, and Samsung users should look at our other recommendations.
Like all of our picks, you can control this device in-person or remotely through your smartphone. Through the Amazon Alexa app, you can change temperature, create a schedule, set notifications and more.
It isn’t a learning thermostat like the Ecobee Premium and Google Nest Learning, but it does monitor your activity to occasionally recommend Hunches. Hunches are essentially suggestions for your existing thermostat schedule based on your use of the thermostat and other Alexa-connected household items.
It's a better fit for smaller spaces, as it does not have built-in sensors to detect whether you are home, and it is not compatible with additional remote sensors.
We’ve linked the model that comes with a C-wire adapter. If you already have a C-wire adapter, you can purchase the Amazon Smart Thermostat without the included adapter for a lower price.
Works with: Amazon Alexa | Control: On-unit, Alexa mobile app | Remote sensors: No | Energy Star Certified: Yes | Installation: C-wire required (adapter included) | Size: 3.56 x 3.56 x 0.84 in
Though most smart thermostats sport a similar interactive design, there are still some things you need to consider when looking at different models.
It’s important to note that not every smart thermostat works with every smart home. Check to see if the smart thermostat you are interested in buying is compatible with the rest of your smart gadgets. Most smart homes use either Amazon Alexa, Google Home, Apple HomeKit or Samsung SmartThings.
If you live in a larger home, look for a thermostat with remote sensors. “Remote occupancy sensors report on precise temperature settings throughout a building,” says Mitchell Klein, executive director of Z-Wave Alliance, the standards development organization dedicated to advancing Z-Wave technology.
Remote sensors can be placed anywhere in the home, monitoring temperature, light, humidity, and motion in locations separated from your main smart thermostat. This can save you money on energy costs by more efficiently heating and cooling your home.
Imagine you live in a two story home where all the bedrooms are on the second floor. It’s nighttime, and everyone is sleeping upstairs. A remote sensor could lessen the heating and cooling priority on the first floor overnight, reducing your energy consumption while keeping the upstairs living space comfortable, says Klein.
Remote sensors can also detect when a house is empty. If no one is home, the smart thermostat might raise or lower the temperature settings, helping you save energy, says Carroll. This home occupancy detection is built-in to some smart thermostats, like the Ecobee Smart Thermostat Premium and Google Nest Learning Thermostat.
The experts we spoke to agreed that the best smart thermostats are certified by Energy Star.
According to Carroll, any smart thermostat with an Energy Star certification has been independently certified with “a full year’s worth of anonymized and aggregated real-world data that demonstrates it can save energy year-round.”
“The more you spend on heating and cooling, the more you could save with an Energy Star-certified smart thermostat,” says Carroll.
Always check the thermostat brand’s site to see that it supports your home energy system — look for the thermostat’s requirements or compatibility section. More complex home heating and cooling systems — such as multistage boilers, heat pumps or dual-fuel systems — may require a more advanced smart thermostat that supports a wider range of heating types. Electric resistance systems, for instance, are only supported by a few thermostats.
You’ll also need to check for a C-wire, the so-called “common” wire segment of some thermostat wiring systems that provides consistent power to a smart thermostat for its Wi-Fi connection and digital display.
According to Carroll, many older homes aren’t designed for C-wires, since older thermostats don’t need them. “If your heating or cooling system is older, most homeowners will want to ask an HVAC technician or electrician for help with any compatibility issues,” says Carroll.
At Select, we work with experts who have specialized knowledge and authority based on relevant training and/or experience. We also take steps to ensure all expert advice and recommendations are made independently and without undisclosed financial conflicts of interest.
Tim Caroll is the press secretary of the U.S. Environmental Protection Agency (EPA) office of public affairs.
Mitchell Klein is the executive director of Z-Wave Alliance, the standards development organization dedicated to advancing Z-Wave technology.
Morgan Greenwald is a former Select senior SEO editor.
Harry Rabinowitz is a reporter at Select who has covered consumer technology for years. For this piece, he spoke with industry and energy experts, and conducted thorough research of top-rated smart thermostats.
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