The Best Smart Thermostats of 2021


Disclaimer: There may be affiliate links, which means I’ll receive a commission if you purchase through the links, but there is no extra cost to you.

If your thermostat isn’t smart, it’s time you got into the game. The best smart thermostats use built-in AI technology to learn your favorite temperature settings, habits, daily schedule, and where people are in the house. 

Using that information, it’ll automatically adjust temperatures for energy cost savings, to sleep better at night, and comfort on the cold winter nights. Try to get your old programmable thermostat to do that. 

Let’s go over the Best Smart Thermostats and help you find the one that best suits you and your smart home. Later in the article, I also offer all the different features and criteria in the How to Choose a Smart Thermostat Buying Guide.

If you’re in a hurry, here are the Top 3 Best Smart Thermostats.

Preview
BEST OVERALL
ecobee SmartThermostat with Voice Control , Black
RUNNER UP
ecobee4 Smart Thermostat with Built-In Alexa, Room Sensor Included
BUDGET-FRIENDLY
ecobee Lite SmartThermostat, Black
Product
ecobee SmartThermostat with Voice Control
Google Nest Learning Thermostat
ecobee3 Lite
Works with Amazon Alexa
Built-in Alexa
Works with Apple HomeKit
Works with Google Assistant
Includes SmartSensor
Estimated Energy Savings
23% Estimated Annually
10-15% Estimated Annually
23% Estimated Annually
Prime
-
BEST OVERALL
Preview
ecobee SmartThermostat with Voice Control , Black
Product
ecobee SmartThermostat with Voice Control
Works with Amazon Alexa
Built-in Alexa
Works with Apple HomeKit
Works with Google Assistant
Includes SmartSensor
Estimated Energy Savings
23% Estimated Annually
Prime
RUNNER UP
Preview
ecobee4 Smart Thermostat with Built-In Alexa, Room Sensor Included
Product
Google Nest Learning Thermostat
Works with Amazon Alexa
Built-in Alexa
Works with Apple HomeKit
Works with Google Assistant
Includes SmartSensor
Estimated Energy Savings
10-15% Estimated Annually
Prime
-
BUDGET-FRIENDLY
Preview
ecobee Lite SmartThermostat, Black
Product
ecobee3 Lite
Works with Amazon Alexa
Built-in Alexa
Works with Apple HomeKit
Works with Google Assistant
Includes SmartSensor
Estimated Energy Savings
23% Estimated Annually
Prime

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

Best Overall: ecobee SmartThermostat with Voice Control

ecobee SmartThermostat with Voice Control , Black
  • Place SmartSensor in the most important room, like your bedroom, child’s room, or office to keep it the perfect temperature
  • Smart Home & Away detects your presence and automatically adjusts the temperature for comfort when you’re home and reduced energy use when you’re away

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

Top pick goes to the 5th-generation ecobee SmartThermostat. The SmartThermostat is the latest offering from ecobee and is the most flexible when it comes to smart home integration with your ecosystems, hubs, and voice assistants. Alexa is already built-in, but Wi-Fi thermostat works well with Google Home and Apple HomeKit and Siri.

This ecobee5 comes with the latest remote sensor, the SmartSensor, that will recognize occupancy presence in other rooms and adjust the temperatures there for comfort. Speakers have also been upgraded, allowing the ecobee to play tunes if you don’t have other smart speakers, like the Echo speakers. 

One of the biggest advantages of ecobee thermostats is ease-of-use. All the functions and settings are clearly easily found on the thermostat and the mobile app. That’s because the user interface and user experience (UI/UX) on both are the same, so you don’t need to learn two different ways to control them. 

ecobee estimates that with eco+ mode activated, energy saving benefits are up to 23% a year on heating and cooling bills. 

The NEW ecobee SmartThermostat Is A Great HomeKit Thermostat

When it comes to installation, ecobee smart thermostats also have a power extender kit adapter that can be used when there is no C-wire to power the thermostat. 

Runner-Up: Nest Learning Thermostat

On Sale
Google Nest Learning Thermostat - Programmable Smart Thermostat for Home -...
  • Programmable smart thermostat that learns your schedule and the temperatures you like and programs itself to help you save energy and stay comfortable
  • Home/Away Assist automatically adjusts itself to an Eco Temperature after you leave, so you don’t heat or cool an empty home

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

The Google Nest Learning Thermostat (3rd Generation) is a popular option for its sleek and modern rounded design. It’s the “Apple” of smart thermostats for its simplistic looks, but it’s still packed full of features. These Wi-Fi connected thermostats look nothing like the traditional thermostats. 

If you already have Google Home speakers at home and using Google Assistant, this is the option for you because they integrate better than other thermostats. The AI learning technology is top-of-the-line when it comes to learning your habits and schedule for energy efficiency. 

The Nest Learning Thermostat also works with remote sensors, Google Nest Temperature Sensor, but it doesn’t usually come with any. You’ll need to purchase them separately, but they’re not too expensive, especially in a 3-pack like this one on Amazon. 

Nest thermostats can only connect to a maximum of 6 remote sensors too, while ecobee can connect to a maximum of 36 sensors. If you have a large home and your HVAC can control multiple zones, you’ll have to consider how many sensors you’ll need for optimal heating and climate control. 

If your furnace doesn’t have a C-wire, you won’t need an adapter with Nest, but that could potentially take power from your furnace control circuits. However, with some HVAC systems such as micro-controller based systems or systems with certain gas valves, a C-wire will be required.

Nest Learning Thermostat 3rd Gen Unboxing/Install/Features/Review

Most Affordable: ecobee3 Lite Smart Thermostat

ecobee Lite SmartThermostat, Black
  • Advanced control from anywhere using your Android or iOS device
  • Integrates seamlessly with your preferred smart home system

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

The ecobee3 Lite Smart Thermostat is one of the Best Budget-Friendly Smart Thermostats and still brings most of the same features as the ecobee5.

The ecobee3 brings the same flexible compatibility with multiple voice assistants and smart home hubs to control the heating and cooling systems. Unfortunately, Alexa isn’t built-in, so you’ll need to purchase a separate Alexa-compatible speaker. The good thing is Amazon Echo Dot smart speakers are inexpensive. 

Remote sensors do not come with the ecobee3, but they are compatible and it’ll be able to recognize occupancy in different areas of your home where the sensors are. 

Budget Friendly: Nest Thermostat E

Google Nest Thermostat E, Smart Thermostat, White, and Google Nest...
  • Frosted Display: Blends into the background and fits into any home. Heat pump is with auxiliary and emergency heat (O/B, AUX)
  • Remote Control: Use the Nest app to change the temperature from anywhere – the beach, the office or your bed.

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

If you have a Google Assistant at home, the Budget-Friendly Smart Thermostat for you is the Google Nest Thermostat E. The Nest E has the same learning AI as the Nest Learning Thermostat, along with many of the same core features. 

The design isn’t as sleek as the Learning Thermostat, but the E is the entry-level model, so savings need to be made somewhere. The Nest E still looks great though and will fit seamlessly with the majority of home designs.

One drawback with Nest’s budget model is it doesn’t support many HVAC systems and two-stage heating and cooling. So you’ll want to check Google’s Nest compatibility checker site.

Great Value: ecobee4 Smart Thermostat

ecobee4 Smart Thermostat with Built-In Alexa, Room Sensor Included
  • SAVE MONEY: Homeowners save up to 23% annually on heating or cooling costs, plus ecobee pays for itself in under 2 years (compared to a hold of 72 degrees).
  • ROOM SENSORS: Place them in the rooms that matter the most and have the temperature balanced throughout your whole home. Measuring both occupancy and temperature, sensors signal your ecobee Smart Thermostat to automatically switch to the right mode for comfort when you’re home or for savings when you’re not. One Room Sensor included, 2-pack sold separately

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

ecobee’s mid-range ecobee4 is a great thermostat that I had to add to the list. The ecobee4 slots in nicely between the ecobee3 and ecobee5 in features and price point. 

The ecobee4 has Amazon Alexa built-in, but not the calling feature  that allows the ecobee SmartThermostat to call phone numbers in the US, Canada, and Mexico for free. 

The ecobee4 does come with one older generation remote sensor, the Room Sensor. The 45 ft. range isn’t as far as the newer SmartSensor at 60 ft., but it still does a good job and works with all the ecobee thermostats. If you have an apartment or smaller house, the Room Sensor should have more than enough range. 

Let’s go through some considerations with choosing a smart thermostat for your home. 

How to Choose the Best Smart Thermostat

Choosing the right smart thermostat hardware for your home is dependent on a number of factors. A smart thermostat offers a range of smart features and benefits that turns it into an energy-saving smart device, while giving you comfortable temperature control all year round. 

Knowing the right questions to ask beforehand will make your choice of the best fit smart thermostat system that much easier. Questions to be considered include:

What type of wiring does my HVAC system use?

Do I need multi-zone capability?

Is remote access important?

In this article, I will help you select the perfect thermostat setup for your needs by answering these questions and more.

Do You Have a Line-Voltage HVAC system?

Determining the type of wiring your HVAC system uses is a crucial step to see if your heating and air conditioning system is compatible with a smart thermostat. To check this, turn off the power to the furnace and remove your existing thermostat from the wall mounting.

If you find two or four thick wires, then your heating system is a line-voltage system that’s most common if you have a floor heater and baseboard option.

A line voltage system (aka high voltage system) uses 220v power and is unlikely to be compatible with common smart thermostats. That’s when you’ll want to go with a Mysa thermostat, which is the perfect option for line voltage systems. 

  • Learn more: Mysa Smart Thermostat Review – The Line Voltage Option

If you discover thinner 18-gauge wires, then you have a low voltage system with central heating that will be compatible with most smart thermostats. 

Does Your System Have a C-Wire?

The next thing to establish is whether your system has a C-Wire. The C-Wire, or common wire, is a wire that feeds continuous power to a thermostat. You can establish whether your system has a C-Wire by checking your current thermostat’s terminals and existing wiring, the C-Wire should be clearly marked.

If you have a C-Wire then your system will be compatible with all smart thermostats. Don’t panic if you don’t find a C-Wire though, thermostats like the Nest range can work without the C-Wire.

Other options include the ecobee range of thermostats which supply an easy-to-install C-Wire adapter if there is no C-Wire present.

Ease of Installation

Most thermostats can be installed with a few simple tools and no need for any technical knowledge. Once the physical installation is complete, then the actual configuration process can vary depending on factors like:

  • The model of the thermostat
  • Whether you intend to integrate it into a smart home ecosystem
  • If you want to set up features like voice control
  • Your existing Wi-Fi router

For example, if you wish to have voice control and don’t own a smart speaker that comes with a digital assistant like Amazon Alexa, then a great choice would be the ecobee SmartThermostat. The ecobee comes with voice assistant Alexa natively integrated and a decent built-in smart speaker. 

For those with a Google Home smart speaker, then the Google Nest range of thermostats are excellent options as they’re designed to pair easily with these speakers for voice commands.

If you’re ever worried about installation, you can hire a heating technician for professional installation. 

Smart Home Integration

As we previously touched upon, integration with your existing smart home devices is one factor that can be crucial when deciding which smart thermostat to purchase. Smart home integration can enhance the functionality and ease of use of a smart home thermostat.

Some examples of smart home systems include:

  • Amazon Alexa
  • Google Home
  • Apple HomeKit
  • Samsung SmartThings

While most thermostats offer compatibility with all the major smart home ecosystems, there are a few things to be aware of when intermixing brands and ecosystems. 

For example, the Third-Generation Nest Learning Thermostat works perfectly with other Google Nest products and Google Home speakers, but they won’t directly connect to other ecosystems.

You’d need a third-party smart home hub like the Starling Home Hub or the Homebridge hub to work with Apple’s HomeKit ecosystem. 

But some thermostats like the ecobee ones or the Honeywell Lyric T5 (aka Honeywell Home Round lineup) will connect without any additional hardware. 

While there are no hard and fast rules when considering smart home integration, there are a few things that can help simplify the choice.

Nest products will integrate seamlessly into Google Home systems, as Nest is a Google company. The latest ecobee range has Alexa built-in. And devices that are compatible with Apple HomeKit will have a sticker on the box saying it’s “Works with Apple HomeKit.”

If you have an existing smart home system, then it is best to check the compatibility of the thermostat before you purchase. That’s how you’ll be able to use all the advanced features of the thermostat. 

Geofencing

Geofencing capability is a feature that many smart thermostats offer now. However, the two brands that have the best abilities in this category are the Nest and ecobee thermostats.

Geofencing is a method of setting control criteria to trigger your heating and cooling depending on the location of your phone.

For example, you can set your heating or air conditioning to switch off if your phone is outside the geofencing radius range to minimize energy usage and save on the utility bill.

On the flip side, it can also switch turn on the HVAC system to a target temperature on once your phone is detected within a certain radius of your home. You’ll be able to come home to a comfortable temperature. 

One factor to be considered when selecting on this basis is the number of phones that can be used to trigger the heating system.

The Nest range of thermostats has the advantage here. Their Geofencing function can be set up on many phones, whereas the ecobee thermostats can only connect to one phone to trigger geofencing features. 

Remote Access

Remote access is one of the key benefits that people look for when considering a smart thermostat. It is also one of the features that most thermostats do offer. 

Remote Access is exactly as it sounds, it is a helpful feature that allows you to remote control your HVAC system from a remote location. This means you can check the status of your heating system, turn it on or off, and adjust schedules from anywhere with an internet connection.

Needing to go to the thermostat’s touchscreen interface to adjust settings and modes isn’t always the most fun. Whether you’re in the other room or on the other side of the world, you’ll be able to access your thermostat as-if you were in front of the touch screen yourself. 

This is especially true with the ecobee thermostats. Their excellent user interface is replicated on the thermostat’s touch screen mobile app, and website. So no need to learn 3 different interfaces to access the thermostat settings.

If you are looking for this feature then you must ensure that it’s a Dual-Band Wi-Fi connected thermostat.  If you have an older thermostat, you can check if there’s a Wi-Fi adapter, but I’d suggest getting a new one, because that’s an extra device that’d you need to troubleshoot if any problems come up. 

Voice Control

If you are looking for voice control as aa smart feature you need, then there are some options to consider. Most smart thermostats when integrated into a smart home system such as Google Home, Apple HomeKit, or Amazon’s Alexa will offer voice control through these systems.

Thermostats paired with Apple HomeKit and Google Home do have a slight advantage over other systems as voice control can be used from any mobile device that has Apple’s Siri or the Google Assistant installed. With an Alexa system, you need to be within range of an Alexa-enabled device to use voice control.

If you don’t have an existing smart device with voice control, the ecobee4 and ecobee SmartThermostat have Alexa built-in for voice control.

Remote Room Sensors

Remote room sensors allow you to set up features such as multi-zone capability (see below). Not all thermostats offer this capability, so if you want a smart thermostat that can work with multiple sensors then it is best to check this before buying.

These remote sensors act as an occupancy, motion, temperature, and/or humidity sensor depending on the specific models. Some sensors have more features than others. 

If it’s an occupancy sensor and it sees that there are people in the room, it’ll take an ambient temperature reading. It’ll then make temperature adjustments to make the ambient temperature comfortable for those in the room. 

Maybe you’re walking around the house, it can also sense that and it’ll help adjust the room you settle into to a uniform temperature from the other room. It can also turn down the previous room’s temperature, since no one’s in there now for energy saving mode. 

The humidity sensor feature is also good if you live in a high humidity are. They can detect the indoor humidity and the thermostat can turn on the A/C to lower humidity when possible. 

Thermostat to thermostat sets vary when purchased, so you’ll want to check to see if any remote sensors are included. For example, the ecobee SmartThermostat usually comes with one of their SmartSensor’s included. While the Nest system sensors have to be purchased separately from the thermostats. 

Multi-Zone Capability

Multi-zone capability offers the user the ability to segregate their home into separate sections and control the heating in each sector individually. This is a standout feature if you have a larger home. 

If you rarely go into your basement, you don’t need to turn on the heating or cooling for that area and it’ll save on your energy costs. You only need to worry about the current temperature in the room or area you’re in, because that’s the only zone that’s working t the moment. 

If you are looking for this as a feature, then in most instances you will need to consider a thermostat that can be paired with multiple sensors discussed earlier. For example, both the Nest and ecobee range can offer this as a feature.

However, there are some thermostats who don’t have multi-zone capabilities. For instance, the Honeywell T5 thermostat offers limited multi-zone capability by only using the Geofencing feature that it uses to determine your location and treat it as the active zone. 

Ease of Use / User Interface complexity

Most smart thermostats offer a range of control methods. All of them have user interface controls that are located on the actual thermostat. These can differ as to how they function.

For instance, the Nest thermostat uses a rotating ring to cycle through the options, whereas the ecobee range uses a touchscreen option. Other thermostats use buttons that are common on non-smart, old-school thermostats. 

Most of them will also offer remote control functions through the use of an app or through a web portal. While most are fairly intuitive to use, the ecobee range are perhaps the slight winners in this category as the interface on the thermostat and through the app are identical.

Smart Thermostat Design and Aesthetics

This might not be a deal-breaker when considering which thermostat to purchase, but if you have narrowed the choice down to a couple of choices, then it could be the deciding factor. It’s often a personal preference and whether or not the thermostat’s design fits with your home’s decor. 

The Nest thermostats have more of a circular, minimalist design and looks modernistic yet unassuming. I liken the Nest design to Apple’s design aesthetic. I do like the stainless steel casing that the Nest Learning Thermostat comes in. 

Ecobee and Hive thermostats are square-shaped with rounded corners. They’re more of an industrial design when compared to the Nest, but it’s still an attractive design to many users.

I prefer the ecobee SmartThermostat design myself, because it’s also much easier to use with the touchscreen and app controls.

Honeywell thermostats give you more of a classic design like traditional thermostats.

Final Thoughts on the Best Smart Thermostats

As you might have noticed, the Top 5 smart thermostats are all ecobee and Google Nest. That’s because they make the best smart thermostats overall. They’re well-known and popular, meaning if you ever have questions about them, you can more easily find solutions. 

Check out a couple articles that go in-depth on both of these thermostat brands: 

ecobee SmartThermostat with Voice Control , Black
ecobee SmartThermostat with Voice Control , Black
Named “Best Overall Smart Thermostat” by Tom’s Guide; Take control of your temperature from anywhere with the ecobee app

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

On Sale
Google Nest Learning Thermostat - Programmable Smart Thermostat for Home -...
Google Nest Learning Thermostat - Programmable Smart Thermostat for Home -...
The Nest Leaf appears when you choose a temperature that saves energy
−14%

Last update on 2021-07-19 / Affiliate links / Images from Amazon Product Advertising API

I hope this post has been helpful in answering some of the questions you might have about choosing a smart thermostat for you.

There are a number of smart thermostat reviews here on the site. You can check out the list of pros and cons for them to help guide your decision making process when it comes time to buy one! 

More Smart Thermostat Lists For Homes

Not all smart homes are the same, nor are home situations. I’ve written a few specific smart thermostat lists for different home scenarios that might be useful for you and your home. 

Best Smart Thermostats For Alexa

Best Smart Thermostats for HomeKit and Apple Siri

Mysa: Best Smart Thermostat for Electric Baseboard Heaters and In-Floor Heaters

Best Smart Thermostat for Multiple Zones

Best Smart Thermostats That Work with Google Home

Best Smart Thermostats for Apartments

Best Smart Thermostat for Airbnb and Rental Properties