Best smart thermostats of 2021

Smart thermostats have exploded in popularity in recent years, so much so that the market is flooded with brands trying to sell you their own version of the technology. That’s a lot of competition, and it can make it difficult to find the right product to match your needs. To make your search easier, we’ve rounded up our favorite smart thermostats of 2021.

Many people don’t know that a smart thermostat can do more than just let you set your preferred temperature. In fact, it can also help save you money, by collecting data on how much energy you actually use — and then showing you the best energy deals on the market. To help you choose the best smart thermostat for your needs, we’ve put together this handy guide.

If you’re like most people, you want to make sure your home is always at a comfortable temperature. Of course, you can do this by just leaving a few options on your thermostat: high, medium, or low. But what if you want something more precise? What if you want your house to be on the exact temperature that you want, every day, without your having to be present in the room?

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A smart thermostat can give you remote control over your heating and air conditioning, ensuring that your home is as cool or toasty as you want it when you get home from work or wherever else, and a good one can monitor environmental conditions and your own preferences over time, adjusting your systems to keep you comfortable while saving you money.

That’s why we’ve spent the past several months putting seven smart thermostats to the test to see which one is ideal for your home.

The best smart thermostat in general

The Nest Learning Thermostat analyzes your behavior and automatically adjusts the temperature in your house. This, along with the user-friendly design, makes it the finest in class.

The best smart thermostat on a budget

The cheaper Nest Thermostat has the same simple interface and easy remote control choices as its more costly brother, but it cannot learn your habits.



The Nest Learning Thermostat never failed to impress after months of testing across different models. When you do need to engage with it, it offers the most straightforward controls, as well as clever features that allow you set it and forget it. The Nest Learning Thermostat is smarter than the typical smart thermostat because it learns from your daily temperature changes and utilizes that information to create patterns.

After a week of use in early summer, the Nest Learning Thermostat had figured out that we preferred it a little cooler overnight and warmer during the day, and that it could switch to Eco when we left the house and then have it ready for when we typically returned, thanks to its geofencing capabilities. Isn’t it amazing? The main catch with the Nest Learning Thermostat is that. It works to identify these trends, adapt as needed, and, as a result, potentially lower your HVAC and energy bills.

The Nest Thermostat, in addition to its smarts, offers three modes: cooling, heating, and eco, all of which may be accessed automatically or manually. Eco sets a temperature that may be a bit higher or colder than you like, but using it while you’re gone or won’t notice it may help you save money on your heating and cooling bills. It’s really useful. And if you ever want to change the temperature, all you have to do is twist the knob.

The Nest Learning Thermostat’s physical design — the greatest user interface of any of the smart thermostats we looked at — makes this simple. The bezel functions similarly to a bigger click wheel. You may increase the temperature by turning it to the right, or decrease it by turning it to the left. It glides and is very nicely constructed. You may also pick an item by pressing down on the bezel or the face. It has a high-end feel to it, which is understandable considering the $249.99 price tag. It’s a joy to use, and getting the results you desire is very simple.

You may use the Nest app on your Android or iOS smartphone to change the temperature or mode when you don’t want to get up. The app’s UI is similar to that of the real Nest Learning Thermostat. You can simply change the temperature, see historical data, and make your own schedules.

The Nest Learning Thermostat can also work with numerous temperature sensors around your house to provide more precise heating and cooling. The numerous sensors distributed over three floors let the Nest detect the temperature more precisely across the room, and therefore make more suitable settings, even in a single zone configuration (as in our tests).

Finally, let’s talk about setup: The Nest Learning Thermostat is compatible with a wide variety of heating and cooling systems. We put it to the test in two different settings: a one-bedroom apartment with one zone and a three-story house with one zone, both with a central cooling and heating system that didn’t have a “C,” or common, wire. The C wire is often used to provide power to a thermostat that is powered directly by house electricity. The Nest Thermostat can operate on its internal battery or an extra power adapter if your HVAC system is especially power-hungry and your house doesn’t have a C wire (some more contemporary systems don’t utilize them).

We made sure our HVAC system was switched off at the breaker before beginning the installation, then removed the old thermostat, installed the Nest Thermostat with the correct wire connections, and linked it through the Nest app (available for Android or iOS). We were off to the races once the app verified our work.

The Nest Learning Thermostat has kept us comfortable throughout our extensive testing, and it is always striving to improve. It’s the finest smart thermostat on the market because of its smarts, which are combined with an intuitive design.


CNN/Jacob Krol

The $129.99 Nest Thermostat has the same well-designed interface and remote app controls as its larger brother, but without the embedded intelligence.

You can still choose between settings manually (cool, heat, cool and heat, Eco mode, or off), activate a preset fast, create a schedule, and regulate the fan (depending on the configuration of your HVAC system, of course). The Nest Thermostat, unlike the Nest Learning Thermostat, will not learn your preferences over time. It can’t track your use and make minor changes throughout the day or week to save your energy cost. You may help yourself to some extent by creating a schedule that includes settings for things like sleep or Eco mode at certain times of day.

You can set up voice control using the Google Home app or via integrations with the Google Assistant or Amazon Alexa, so you have lots of remote control choices. You may then say things like, “Hey Google, chill it down,” or “Alexa, set the living room thermostat to 71 degrees.”

If you prefer tactile contact, the $129 Nest Thermostat has a capacitive touch sensor on the top right side instead of the Learning Thermostat’s circular movable bezel. You can change the temperature by sliding your finger up or down, and you can also touch it to perform an action. And, to be honest, we did got the hang of it after a few days of usage, but it’s not quite as intuitive as the click wheel on the $249.99 Nest Learning Thermostat. Getting anything done may need more interactions in the end. You must touch it once to bring up a menu, scroll to the appropriate icon, then tap it again to choose it while switching between cooling modes. However, you can adjust the temperature by swiping up or down during the day.

Surprisingly, the Nest Thermostat does not utilize the Nest app. Although this is part of a broader Google reorganization, setup and control are done via the main Google Home app. It’s a simple interface, and if you’re currently using this ecosystem for your smart home, you’ll feel perfectly at home. The Nest Thermostat’s interface in the Home app is designed to look like the real device, with the programmed temperature in the middle and the actual temperature (together with humidity) right below it.

The Nest Thermostat comes in four colors: Snow, Charcoal, Sand, and Fog. While you may be tempted to touch the rectangular display coated in a mirror finish on the circular device, we don’t suggest it. The Nest Thermostat may be powered by a C wire, two AA batteries, or a power adapter, much like the Learning Thermostat.

Google has created a beautiful device here, but it isn’t very tech-savvy or has a great user interface. Nonetheless, the $129.99 Nest Thermostat excels as a cost-effective and user-friendly thermostat that allows you to effortlessly manage the temperature of your house.

Before installing any of the seven thermostats, we double-checked that we were doing it safely. This included cutting the electricity to our HVAC systems by turning off the breaker. We next took off the non-smart thermostat that was with the house and started installing the thermostat that was being tested.

With each installation, we followed the supplied instructions, as well as any onboarding instructions provided by the app. We made particular note of how easy the directions were to follow, and the app was assisting us throughout the process. We evaluated the various modes after a successful installation to guarantee optimal operation. We spent several days with each thermostat to acquire a feel for it and allow it to calibrate.

We tried control on the same Wi-Fi network with each app as well as when using cellular while out of the home. We also tested the thermostat’s geofencing capabilities if it had them. We utilized the thermostats with all supported smart home ecosystems in addition to managing them via the companion app for each device.

Finally, we looked at the duration of each unit’s warranty and what was covered by it. Ecobee 3 Lite ($169).

The Ecobee 3 Lite is the brand’s entry-level smart thermostat, and it does what it sets out to achieve. In our tests, the bigger touch screen was simple to use and mirrored the companion app for Android or iOS. It’s essentially a matter of personal taste, but we missed having physical controls for the heating and cooling.

This smart thermostat, like the complete Ecobee Smart Thermostat With Voice Control, comes with a power adapter in the package, which is useful if your setup lacks a C wire for direct power to the device. It’s a simple enough task to install, but it adds some time to the process. The Ecobee 3 Lite also works with a variety of smart home ecosystems, including Amazon Alexa, Apple HomeKit, Google Home, and SmartThings. sells the Ecobee Smart Thermostat with Voice Control for $248.64.

The Ecobee, which is more costly, is more than simply a smart thermostat. This really is a smart speaker on your wall, with a speaker and a pair of microphones on board, and it can be used as an Amazon Alexa smart speaker for playing music and answering questions of all kinds.

It also offers a heating and cooling control experience that is almost similar to the Ecobee 3 Lite. The Ecobee app for Android or iOS, as well as a large touch screen on the front of the device, will let you manage everything. We like the Nest Thermostat’s entire installation procedure and settings.

Honeywell Home T5+ ($124, initially $150; is a smart home security system.

If you have other Ring devices, the Honeywell is a good option since it works with the Ring ecosystem right out of the box. Aside than that, they are very ordinary thermostats. A power adaptor is included in the package, much like the Ecobees. With a black square shape, it has a little more of a hefty appearance, but it’s still pretty simple to operate. We should also mention that connecting the T5+ to our Wi-Fi network took a few attempts.

Honeywell Home T9 ($143.57, originally $199.99; Honeywell Home T9 ($143.57, originally $199.99) Honeywell Home T9 ($143.57, originally

The Honeywell Home T9 is a little pricey at $199.99, but it doesn’t have a design that fits that price range. You’ll need to provide power through a C wire or the supplied adaptor, and then installation is very straightforward. The T9 also supports geofencing, which allows you to set it to an eco temperature while you’re away from home and then turn it back on as you get closer. Amazon Alexa, Apple HomeKit, and Google Home are all supported by this smart thermostat.

Wyze Thermostat (; $78.98)

The Wyze Thermostat was the most inexpensive of the group, at $59.99, and although it performed well in our tests, the design was ultimately unappealing. It has a knob style that is similar to the Nest Learning Thermostat, although it isn’t as smooth to use. To engage and set the temperature, it required a fairly strong click. The Wyze Thermostat is also compatible with Alexa and Google Assistant.

The build quality wasn’t fantastic, and the setup took a little longer, but for an extra $70, we think the basic Nest Thermostat is the best option.

More from CNN Underscored’s hands-on testing may be found here:

Just as the world was rushing headlong into the age of smart home, the smart thermostat was in its relative infancy. Google’s Nest was the first to hit the market in August 2014, but the rest of the industry followed. The category of smart thermostats has exploded in the space of two years, with a flood of hardware hitting the market to claim the title. Your smart thermostat will be there to help you save energy and money, and it will be able to do this from a distance.. Read more about best smart thermostat reddit and let us know what you think.

Frequently Asked Questions

Is Honeywell or Sensi better?

Honeywell is a better option for those who are looking for an affordable price.

Whats the best thermostat to buy?

The best thermostat to buy is the Honeywell RTH6300WF.

Are smart thermostats really worth it?

Smart thermostats are a great way to save money on your heating and cooling bills. They can help you save up to 20% on your energy bill, which is a significant amount of money.

Related Tags

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  • best smart thermostat for multiple zones
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