The Best Smart Thermostats for a More Energy-Efficient Home

We recommend the Ecobee Smart Thermostat with Voice Control

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The Spruce / Amelia Manley

Smart thermostats are more efficient than conventional thermostats, so they can save you time, increase your comfort, and even reduce home heating and cooling costs. “One of the top benefits of owning a smart thermostat is the ability to automatically adjust the temperature based on your schedule,” says Bariyah Faisal of Cielo WiGle. “This can help to significantly reduce your energy usage, as you're not needlessly heating or cooling an empty home.”

We researched dozens of smart thermostats to find the best ones based on factors like ease of use, advanced features, smart home integration, and performance. The Ecobee Smart Thermostat with Voice Control is our top recommendation due to its overall performance, a remote sensor that allows you to monitor an additional room, a built-in microphone and speaker combo, and built-in Siri and Alexa.

Here are the rest of our picks for the best smart thermostats.

Our Top Picks

Best Overall

Ecobee Smart Thermostat with Voice Control

4.9
ecobee SmartThermostat with Voice Control

Amazon

What We Like
  • Integrated voice controls

  • One remote sensor included

  • Includes a decent speaker

What We Don't Like
  • Big bezel around the display

  • Scheduling can be complicated

  • No built-in Google Assistant

The Ecobee Smart Thermostat with Voice Control has many great features, comes with a remote room sensor with the option to add more, and works with all of the major smart home systems, which is why it’s our pick for the best overall smart thermostat.

This model is the fifth generation of Ecobee’s smart thermostat hardware. It has a color touchscreen display, built-in speaker, voice controls supported by Amazon’s Alexa virtual assistant, and even supports advanced Alexa functionality like calling, messaging, and the drop-in intercom feature. The quality of the speaker is similar to an Echo Dot, which is a big improvement over previous generations of Ecobee hardware.

If you don’t use Alexa, the fifth-generation Ecobee also has built-in support for Siri as long as you have a HomePod or HomePod Mini on your network. You can also connect to Google Home, but Google Assistant doesn’t work directly on Ecobee. That means Google Home users need to issue voice commands to the Ecobee through a connected Nest speaker or the phone app.

Ecobee supports remote sensors that monitor both temperature and presence, and you get one when you buy the thermostat. This sensor allows the system to monitor the temperature at the thermostat and somewhere else in your home, know whether people are there, and adjust the heating or cooling accordingly. Small homes get by just fine with one sensor, but you can add up to 32 sensors if you have a large home with many rooms across multiple floors.

Price at time of publish: $220

Dimensions: 4.29 x 1 x 4.29 inches︱Power Source: AC/DC, includes power extender kit︱Works With: Amazon Alexa, Google Assistant, Apple HomeKit, and more︱Display: 3.5-inch LCD touchscreen

Best Budget

Amazon Smart Thermostat

Amazon Smart Thermostat

Amazon

What We Like
  • Excellent Alexa integration

  • Energy usage reports

  • Responsive touchscreen

What We Don't Like
  • No support for Google Assistant or HomeKit

  • No remote sensor support

  • Needs a C-wire

The Amazon Smart Thermostat has an understated design and a rock-bottom price tag, but that unassuming exterior hides a surprising amount of functionality. Amazon partnered with Resideo to manufacture this smart thermostat, and its hardware has a lot in common with the much more expensive Honeywell T9 and T5 thermostats. It also leans on Alexa and the Hunches feature to approximate Google’s best-in-class learning functionality, which allows it to automatically adjust the temperature in your home based on past preferences and current activity.

While this is the best option for adding smart functionality to an HVAC system on a budget, the glaring issue is that it only works with one smart home system. If you don’t use Amazon’s Alexa, that may be an issue. This thermostat doesn’t support Google Assistant, HomeKit, or SmartThings. Alexa integration is seamless, but that’s only useful if you use Alexa in the first place.

Price at time of publish: $60

Dimensions: 3.56 x 0.84 x 3.56 inches︱Power Source: AC/DC, C-wire required︱Works With: Amazon Alexa︱Display: Basic LED with touch controls

Best With Machine Learning

Google Nest Learning Thermostat

4.9
Nest Learning Thermostat 3rd Gen

Home Depot

What We Like
  • Attractive, colorful display

  • Intuitive controls

  • Great mobile app

What We Don't Like
  • No HomeKit support

  • Doesn’t come with remote sensors

The third-generation Nest Learning Thermostat uses Google’s advanced machine learning technology to learn your daily routines and automatically adjust the temperature in your home, which is why it’s our pick for the smartest smart thermostat around. It can remember the temperature selections you make throughout the day, determine when you’re home and away, and eventually set the temperature just right without any further input.

The Nest works well with Google Assistant and Alexa for voice controls but doesn’t have HomeKit support. Voice controls and smart home integration aren’t absolutely necessary, though, since you typically only need to change the temperature manually whenever you need it to be hotter or colder than your established norm. This model also lacks a remote sensor, but you can purchase Nest Temperature sensors separately for more control over conditions in certain spaces.

Price at time of publish: $300

Dimensions: 3.3 x 1.21 x 3.3 inches︱Power Source: AC/DC, battery (for backup power)︱Works With: Google Assistant, Nest, Amazon Alexa︱Display: 2-inch color LCD

Best Display

Emerson Sensi Touch Wi-Fi Smart Thermostat

Sensi Touch Wi-Fi 7-Day Programmable Thermostat

The Home Depot

What We Like
  • Responsive full-color touchscreen

  • Great mobile app

  • Supports geofencing

What We Don't Like
  • Doesn’t work with remote sensors

  • No IFTTT support

  • No occupancy sensor

The Sensi Touch Smart Thermostat features a big, colorful 4.3-inch full-color LCD touchscreen that sets it apart from the crowd. The display shows the current temperature prominently instead of the set temperature, so you can always see how hot or cold it is at a glance, even from across the room. The screen is smooth and responsive as well, so it’s as functional as it is attractive.

The thermostat controls allow you to set up to four temperature changes per day, and the mobile app makes scheduling easy—letting you add additional changes in increments as small as 15 minutes. It doesn’t have a presence sensor, and you can’t add remote sensors, but it does support geofencing. That means you can have the heat or air conditioning turned on only when you’re actually home, which the system determines based on the location of your phone.

Price at time of publish: $169

Dimensions: 5.63 x 1 x 3.2 inches︱Power Source: AC/DC, C-wire required︱Works With: Amazon Alexa, Google Assistant, Samsung SmartThings, Apple HomeKit︱Display: 4.3-inch full-color LCD touchscreen

Best With No C-Wire

Sensi Emerson Sensi Wi-Fi Smart Thermostat

Emerson Sensi Wi-Fi Smart Thermostat

Amazon

What We Like
  • Easy installation

  • Custom scheduling

  • Supports geofencing

What We Don't Like
  • Screen looks dated

  • No IFTTT support

The Sensi Smart Thermostat could be what you’re looking for if your existing thermostat doesn’t have a C-wire and you don’t want to pay to install it. You can connect it to a C-wire if your system already has one, but it’s fully functional even without that extra power source. It does run on batteries, which means popping it open to install fresh ones from time to time, but that’s unavoidable if you want a smart thermostat that doesn’t require a C-wire.

The monochrome display is easy to read but looks a little dated compared to other smart thermostats. The app looks better and allows you to control the thermostat remotely. This thermostat supports highly customized scheduling to control the temperature at different times of day and on different days. It also supports geofencing to switch off when you leave the house and back on when you return.

Price at time of publish: $127

Dimensions: 5.88 x 1 x 3.75 inches︱Power Source: Battery, AC/DC︱Works With: Amazon Alexa, Google Assistant, Samsung SmartThings, Apple HomeKit︱Display: 5-inch monochrome

Best for Big Houses

Honeywell Home T9 Wi-Fi Smart Thermostat

Honeywell Home T9 Wi-Fi Smart Thermostat

Amazon

What We Like
  • Monitor temperature, humidity, and presence

  • Add up to 20 sensors

  • Ventilation and humidifier integration

What We Don't Like
  • Choose geofencing or scheduling

  • No presence sensor on the thermostat

  • Need multiple units for zone control

The Honeywell Home T9 Smart Thermostat with Sensor is the best smart thermostat for large homes because it comes with a remote sensor, and you can add up to 19 additional units. It’s difficult to regulate the temperature in large homes with a single thermostat and no zone control, but the T9 and its remote sensors do the best job possible. Instead of only relying on temperature readings taken at the thermostat itself, the T9 considers the temperature and humidity throughout your home when making adjustments.

The Honeywell T9 doesn’t have zone control, but you can use multiples of this thermostat model if your house has multiple zones. Each zone needs its own thermostat and sensors, and then you can control the entire system through the Resideo app or your connected smart home system. For smart home connectivity, the T9 supports Alexa, Google Assistant, SmartThings, and HomeKit.

Price at time of publish: $180

Dimensions: 3.7 x 0.94 x 4.92 inches︱Power Source: AC/DC, includes adapter︱Works With: Amazon Alexa, Google Assistant, Samsung SmartThings, Apple HomeKit︱Display: Full-color touchscreen

Best for HomeKit

Ecobee 3 Lite

Ecobee 3 Lite

Ecobee

What We Like
  • Works with remote sensors

  • Occupancy detection

  • Simple display is easy to read

What We Don't Like
  • No native geofencing

  • Sometimes displays inaccurate weather

  • Remote sensors cost extra

The Ecobee3 Lite is an excellent low-cost alternative to our top overall pick, the Ecobee Smart Thermostat with Voice Control, with the same fantastic HomeKit support at a much lower price. Ecobee’s HomeKit support is so strong, in fact, that it’s the only smart thermostat manufacturer recommended by Apple. HomeKit integration even allows you to implement geofencing, a feature that adjusts your thermostat based on whether you’re home, which the Ecobee3 Lite can’t do on its own. In addition to excellent HomeKit support, the Ecobee3 Lite also supports Alexa, Google Assistant, and SmartThings.

While this smart thermostat doesn’t come with remote sensors, it supports these units, which you can purchase separately. Remote sensors allow you to monitor the temperature in different areas of your home and set the Ecobee3 Lite accordingly, and they also work with the occupancy detection feature. That means the Ecobee3 can automatically adjust the temperature if it notices the presence of someone in a room where you have placed a sensor.

Price at time of publish: $150

Dimensions: ‎4 x 21.4 x 4 inches︱Power Source: AC/DC, power extender kit included︱Works With: Apple HomeKit, Amazon Alexa, Google Assistant, Samsung SmartThings︱Display: 3.5-inch full-color LCD touchscreen

Best for Baseboards

Mysa Smart Thermostat

Mysa Smart Thermostat for Electric Baseboard Heaters

Amazon

What We Like
  • App can help you save money

  • Unique minimalist design

  • Works with Alexa, Google Assistant, and HomeKit

What We Don't Like
  • Display is too bright at night

  • Slow touch response

  • Display doesn’t convey much information

The Mysa Smart Thermostat is the best option if you have electric baseboard heaters. It features a slick, minimalist design with touch controls that allow you to easily adjust the temperature right on the thermostat. It can also connect to your Wi-Fi network to facilitate app control. When connected to your Wi-Fi network, this thermostat supports voice commands and integration with Alexa, Google Assistant, and HomeKit.

While the display is less informative than other models, the Mysa app allows you to monitor and control all of your Mysa smart thermostats from a central location. That includes scheduling when each heater should turn on and off, geofencing to turn the heaters off when you leave and on when you get back, and manual controls. The app also provides energy insights, which allow you to see exactly how much power your heaters are using and make adjustments to save money on your power bill.

Price at time of publish: $139

Dimensions: 3.5 x 0.8 x 5.1 inches︱Power Source: AC/DC︱Works With: Amazon Alexa, Google Assistant, Apple HomeKit︱Display: LED

Best for Ductless A/C

Cielo Breez Plus Smart Air Conditioner Controller

Cielo Breez Plus Smart Air Conditioner Controller

Amazon

What We Like
  • Displays both humidity and temperature

  • Works with split and window A/C units

  • Scheduling and geofencing

What We Don't Like
  • Doesn’t work with HomeKit

  • Basic LCD display

  • On-device scheduling difficult

If you have a split, window, or portable air conditioning unit controlled by a remote, consider the Cielo Breez Plus. This smart thermostat allows you to remotely manage your air conditioning unit through a phone app, use voice commands if you have Alexa, Google Assistant, or Siri, and control settings directly on the device itself. The display is less advanced than most smart thermostats, and on-device scheduling can be less straightforward compared to competitors. However, you can set a schedule to adjust the temperature based on the time of day, and there’s a geofencing option to automatically turn the A/C off when you leave and back on when you get home.

Setup is easier with this smart thermostat than most others because it controls your A/C unit wirelessly using the same method as your existing A/C remote. The only caveat is that you need to install the Cielo Breez Pro in an area with a clear line of sight between it and your A/C unit.

Price at time of publish: $150

Dimensions: ‎4.33 x 1.02 x 4.33 inches︱Power Source: 5- or 12-volt power adapter︱Works With: Amazon Alexa, Google Assistant, Siri, IFTTT︱Display: LCD

Final Verdict

Our top pick for the best overall smart thermostat is the Ecobee Smart Thermostat with Voice Control. It comes with a remote sensor that helps you monitor and control the temperature in your home, onboard Alexa and Siri, and a built-in speaker that lets you listen to music from Spotify. We also highly recommend the Google Nest Learning Thermostat. Its advanced technology takes all the guesswork out of setting your thermostat for optimal comfort and energy savings.

What to Look For in Smart Thermostats

Compatibility

The thing that makes smart thermostats smart is that they can connect to your home network via Wi-Fi and integrate with other smart home devices. “Smart home integration is important,” says Faisal. “Are you using Alexa, Google Assistant, SmartThings, or another service? You must check if your thermostat is compatible.” If you select a smart thermostat that doesn’t work with your existing smart home system, you won’t be able to fully use its smart features or control it with voice commands.

Features

The level of features included with a smart thermostat directly affects the price. The most basic feature is the ability to remotely control the thermostat via a phone app, which every smart thermostat can do. Other useful features include built-in virtual assistant functionality for voice control and the option to add additional room sensors, which could be particularly useful for large homes. If you want more control over your system, you might look for advanced traits like geofencing, to turn the system on and off depending on whether you’re home, and automatic controls that use machine learning to set the temperature automatically.

Ease of Installation

There are a few levels of difficulty to consider when looking at smart thermostats, and difficulty also depends on the type of thermostat you’re replacing. If your old thermostat had a C-wire, installation is a matter of removing the old thermostat and wiring in the new one. If your old thermostat didn’t have a C-wire, the easiest option is to look for a smart thermostat that doesn’t need this wire. The other option is to install a C-wire adapter, which is a more complicated job.

FAQ
  • What is a smart thermostat?

    Smart thermostats connect to your home network via Wi-Fi, allowing you to control your heating and cooling remotely via an app. Every smart thermostat has that basic functionality, but some can learn your routine and adjust the temperature automatically, make adjustments based on where people are in the house, and switch on and off depending on whether you’re home.

  • How do you install a smart thermostat?

    Installation varies from one system to another, but the general procedure is to switch off power to your HVAC system, remove the old thermostat, wire in the smart thermostat, and turn the power back on. If your old thermostat didn’t have a C-wire, then you also have to install a C-wire adapter or run a new wire from the HVAC system to the thermostat. The final step in the installation and setup process is to connect the thermostat to your Wi-Fi network.

  • Is a smart thermostat worth it?

    If you have a Wi-Fi network at home, and especially if you already have other smart devices, you will probably find it worth your while to install a smart thermostat. “A smart thermostat provides several benefits, mainly in terms of comfort, convenience, and especially energy savings,” says Faisal. “For example, you can program it to lower the temperature when you're away from home or asleep and then raise it again shortly before you return.” That can save you money while making your home more comfortable at the same time.

    “Other advantages include tracking energy usage, learning your cooling/heating patterns, and providing maintenance alerts,” adds Faisal. She notes that “it's just so convenient not to have to get up and enter settings on your thermostat. You can view and adjust your home temperature settings from anywhere using your phone.”

Why Trust The Spruce?

This article was written by Jeremy Laukkonen, a freelance writer and product tester for The Spruce. His home HVAC system is managed to perfection by a smart Honeywell thermostat configured to work with Alexa Hunches, and he has over a decade of experience reviewing electronics for outlets like Lifewire and Digital Trends, in addition to the Spruce.

To get a better handle on the inner workings of smart thermostats, Laukkonen contacted Bariyah Faisal, content specialist from Cielo WiGle. With Faisal’s insights, Laukkonen looked at smart features like automatic scheduling, geofencing, and energy usage reports alongside factors like compatibility and ease of installation to identify the best smart thermostats on the market.

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