The 8 Best Smart Thermostats of 2021

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Our Top Picks

Best Overall: Nest Thermostat at Amazon

"It's beloved for its ability to "learn" your temperature preferences and routine in under two weeks."

Best Overall, Runner-Up: Honeywell Smart Wi-Fi Color Touch Thermostat, Model RTH9585WF at Home Depot

"You can customize the color of the bright and generously sized LCD display."

Best for Multiple Zones: Ecobee4 Smart Thermostat at Lowe’s

"You can purchase additional room sensors to expand its temperature monitoring capabilities."

Best Battery-Powered: Emerson Sensi Wi-Fi Smart Thermostat for Smart Home at Home Depot

"Geo-fencing lets the thermostat determine if you’re home or away."

Best for Alexa: Ecobee Smart Thermostat with Voice Control at Best Buy

"It's designed with Alexa in mind, but can also be used with Google Home and Apple HomeKit."

Best for Google Home: Nest E at Home Depot

"Its frosted plastic housing blends into most environments."

Best for Air Quality: GLAS Smart Thermostat by Johnson Controls at Amazon

"Beyond the standard temperature information, it also gives you insights on humidity levels, CO2 readings, and more."

Best Budget: Honeywell Home Wi-Fi Programmable Thermostat, Model RTH6580WF at Home Depot

"It doesn't have the fancy display screen, but you'll spend more time using the app than the screen anyway."

Smart thermostats offer convenience and energy-savings in one compact device. Typically costing $250 or less, many people see significant savings in their heating and cooling bills when using a smart thermostat that offers expanded programming and wireless control of their HVAC functions.

If there is one thermostat that can be credited with bringing the concept of smart thermostats to the masses, it might be the Google Nest. This popular smart thermostat offers an easy-to-use interface, shiny round thermostat housing with a bezel in multiple finishes, and a glowing screen that provides at-a-glance information regarding your home’s temperature. Beloved for its ability to ‘learn’ your routine in just a week or two, the Nest is a great hands-off smart thermostat that doesn’t require extensive programming or customization to optimize your home’s energy usage. It also is designed to work intuitively with the Google Home ecosystem and supports voice control from Amazon Alexa. However, it doesn’t integrate with Apple HomeKit and instead requires you to adjust the thermostat from within the Nest iOS app. The Nest works with many different home heating and cooling set-ups. A C-wire connection is best for powering the LED display, but it is possible to install without a C-wire by alternative wiring.

The newest Nest is the 3rd generation of this best-selling smart thermostat. While the aesthetics remain largely unchanged, the display is slightly larger than the original model at 2.1 inches versus 1.8 inches and the resolution has been bumped up to 480 pixels per inch versus 320 pixels. In tech terms, the biggest advancements include an additional 3 temperature sensors inside the unit compared to the original Nest, along with geofencing technology that enables the thermostat to use your phone’s position to determine if your home or away (note that the Nest is able to track multiple phones).

In day-to-day usage, many users appreciate the enhanced Farsight ability of the Nest 3rd generation smart thermostat. Instead of needing to directly approach the thermostat to see the temperature, time, or weather read-outs, the Nest can recognize your presence as soon as you enter the space and show you the selected information at a glance from across the room. In addition, Nest has made room sensors available that feed information to your thermostat from various locations in your house, but they are sold separately and are rather pricey.

For another leading option in the smart home thermostat space, consider the Honeywell Smart Wi-Fi Color Touch Thermostat. While some other brands claim more name recognition when it comes to smart thermostats, Honeywell is a leading brand in the space and this model is definitely worth your consideration. Note that this model does require a C-wire for correct installation.

Honeywell model RTH9585WF costs less than $200 and integrates with a variety of smart home systems, including Amazon Alexa, Samsung SmartThings, Google Home, and IFTTT functions. Plus, with Wi-Fi capability, you can use Honeywell’s app to directly monitor and adjust HVAC settings from anywhere—whether you’re on vacation or on your couch! Like a few other models of smart thermostats, this model also is equipped with response technology that enables the system to ‘learn’ your routine and optimize heating and cooling functions to conserve energy. One neat feature that users comment on is the ability to customize the color of the bright and generously sized LCD display.

The 8 Best Thermostats of 2021

One of the leading options for smarter temperature control is also our top pick as a smart thermostat for multiple zones or rooms, the Ecobee4. This full-featured model comes with an included room sensor, which monitors the temperature in whichever area you set it up. However, additional room sensors are available to expand the monitoring capabilities; one Ecobee4 can receive data from up to a whopping 32 room sensors. The best thing about the Ecobee4 as a smart thermostat for multiple zones is the model’s ‘Follow Me’ functionality. This feature enables the thermostat to use motion sensors built into the room sensor to detect which rooms you’re spending time in and which rooms it can conserve energy in.

One thing you should know is that the main point of this smart thermostat for multiple zones is to allow the system to better monitor the temperature throughout your house and balance energy usage in unoccupied rooms. However, it doesn’t allow you to set an individual temperature for each space with a room sensor. To do so would require multiple smart thermostats controlling various sets of rooms.

The 8 Best Programmable Thermostats of 2021

Many smart thermostats require a C-wire connection to power the vivid, touchscreen display, but not all furnaces have a C-wire connection. If you’re looking for an alternative option that doesn’t involve stealing power from other wires within your home’s HVAC system, a battery-powered smart thermostat is an option to consider and is generally also easier to install.

For most conventional HVAC configurations, the Emerson Sensi Wi-Fi Smart Thermostat can operate on just battery power when no C-wire is available. The only exceptions are for homes that have only a heating system, only a cooling system, or a heat pump. While the display isn’t as flashy and eye-catching as other major players in the space that require a C-wire for constant power, users agree that the LCD screen is still easy to read and offers a button for 10 seconds of display lighting. This smart thermostat is equipped with Wi-Fi and allows you to control your home’s HVAC system via the free app or by using Amazon Alexa, Apple HomeKit, Google Assistant, and Wink home automation platforms. You can also enable geofencing, which lets the thermostat determine if you’re home or away to optimize energy usage.

This is also very easy to install, according to reviewers. Plenty of users report installing the Emerson Sensi thermostat in 30 minutes or less. Many people have opted to skip professional installation and have had no trouble completing the process and having their new smart thermostat up and running in no time.

The 8 Best Smart Thermostats of 2021

Ecobee thermostats have become known for their seamless Amazon Alexa integration, and the newest model to the line-up, the Ecobee Smart Thermostat with Voice Control, is the most advanced smart thermostat for Alexa yet. Like the Ecobee4, the newest Ecobee model has Amazon Alexa built into the thermostat housing—no separate Alexa device required.

In addition to the standard temperature controls you’d expect, the Ecobee Smart Thermostat with Voice Control lets you make play music, get the latest news, control other smart home devices, and even make hands-free phone calls. Despite the fact that this smart thermostat is clearly designed with Alexa in mind, it’s also very intuitive to use with other smart home platforms, like Google Home and Apple HomeKit.

For a smart thermostat that fits right into your Google Home ecosystem, check out the affordable and feature-packed Nest E. Like Google’s pricier Nest smart thermostat, the Nest E is built to integrate with other Google Home products and offer you easy app or voice control of your home’s temperature.

The Nest E features a frosted plastic housing that blends into most environments but isn’t quite as flashy as the brightly colored LED and metal housing of the flagship Nest. Aesthetics aside, reviewers are big fans of how easy and intuitive it is to use the Nest E. Ask Google to turn down the temperature if you’re feeling warm or leave it up to the system to learn your routine and automatically optimize your home’s energy usage.

If you’re concerned with knowing more than just the ambient temperature inside your home, a smart thermostat with air quality insights is a great option. While some models include humidity, the GLAS smart thermostat from Johnson Controls includes information regarding humidity, total VOCs, and CO2 readings. More than just eye candy for your wall, it also uses a Wi-Fi connection to keeps tabs on outdoor air quality conditions with information on allergens, the air quality index, and UV index.

Warren Johnson, who founded Johnson Controls, invented the first electric room thermostat. So it’s no surprise the company continues to look to advance the smart thermostat with such a full suite of information. The GLAS thermostat also commands attention with its sleek, high-tech OLED screen, but reviewers wish that there was an option to keep the screen in display mode rather than manually activating it each time you want to know the current temperature or air quality. Additionally, some people have found the app to be slow and cumbersome when compared to other smart thermostats on the market.

A smart thermostat can save you big bucks on your utility costs but might also mean investing $200 or more into a new thermostat. If you’re looking for a budget model that still provides you wireless control of your home’s heating or cool functions, this affordable but frills-free smart thermostat from Honeywell is a great option for under $75. It requires a C-wire for installation but is an otherwise simple swap if you’re looking to upgrade your thermostat.

The Honeywell Home Wi-Fi Thermostat looks similar to conventional units, but integrates Wi-Fi and allows you to control your home’s temperature settings from the Honeywell app. Even better, this thermostat can be controlled by popular smart home systems like Amazon Alexa, Google Assistant, IFTTT, and Samsung SmartThings.

The biggest thing you’ll notice is the lack of a fancy display screen, but as one user points out, the idea behind a Wi-Fi smart home thermostat is to be able to control your thermostat from anywhere. Thanks to app access or with help from the Honeywell Skill on Amazon Alexa or other smart home assistants, you’ll spend more time adjusting the temperature from your device than you will standing in front of the screen—making that fancy feature non-essential for shoppers of a budget smart thermostat.