The best smart thermostats of 2021
Smart thermostats do more than manage your home’s heating and cooling system. These app-enabled smart home devices make it possible to adjust your thermostat from your phone whether you’re on the couch, at the grocery store or on vacation — anywhere your phone or mobile device is connected to a Wi-Fi or cellular network. Many smart thermostats also work with Alexa, Google Assistant and Siri now too, giving you yet another way to adjust your settings with remote access to your smart home systems.
Some smart thermostat systems also use smart features like a motion sensor to determine if you’re home or away and automatically change the temperature — both heating and cooling — for you, without you having to fiddle with your HVAC system. Others rely on a geofencing radius: Once you get a certain distance from your home, they automatically switch to away mode and then back to home mode when you return. Then there are features like remote sensors, a power extender kit, thermostats that work with existing infrastructures (in other words, that are compatible with Apple HomeKit) and, of course, thermostats that measure your energy usage so that your home can be more energy efficient. Truly, a smart home thermostat is an energy-saving smart device that’s good for both the environment and your wallet.
Even better, these options offer way more than a programmable thermostat — you want a learning thermostat that gets better at regulating the temperature to suit your preferences.
To accompany these modern features, many connected heating and cooling systems boast innovative designs. From a rounded shape to a responsive touchscreen, smart thermostats look a lot different than your traditional thermostat. They can also send you smart alerts, sync with the rest of your smart home devices and some even respond to voice commands.
Let’s explore the available options model by model. We’ll highlight what makes each model stand out from the rest and ultimately pick an overall winner of the best smart thermostat from the pack. We update the list periodically, but here’s a list of smart thermostats we’ve tested recently:
The Ecobee Smart Thermostat is my favorite pick for best smart thermostat available today. Yes, it’s expensive at $249, but it has the performance and features to back it up — especially if you want to talk to Alexa without having to buy an Amazon Echo. If you don’t want or need an Amazon Alexa speaker, the $169 Ecobee3 Lite Wi-Fi thermostat is also a great option.
The Nest Thermostat is an Alexa- and Google-Assistant-enabled smart thermostat from Google — and it’s only $130, or even less. Compared to the high-end $250 smart thermostats, this model offers a great value. It also looks nice, is easy to install and use in the Google Home app (or with a voice command; compatible smart speakers and displays sold separately) and performs well.
If you’re searching for a solid entry-level smart thermostat, the Nest Thermostat is an excellent option.
The Honeywell Home T9 is a $200 smart thermostat from Resideo. The T9 works with Alexa and Google Assistant and offers reliable performance and a solid app. The device also comes with remote humidity, proximity and temperature sensors, making it the smartest sensor accessory around. Nest’s sensor only provides ambient temperature readings, while Ecobee’s sensor only has temperature and proximity detection capabilities.
Testing a thermostat
Let’s talk about testing. Smart thermostats start with the installation. Installations can vary widely from thermostat to thermostat and between HVAC systems, but there are some basic steps required for installing these devices. As always, consult a professional installer if you have any questions about the setup process. Here are the general steps:
- Turn off power to your thermostat at the circuit breaker
- Remove the old thermostat
- Install the thermostat’s base plate with the included screws
- Attach the wires to the wire terminals
- Snap on the faceplate
- Turn on power at the circuit breaker
Was the thermostat setup especially difficult to install? If so, why? Certain models require a C-wire, for example, which can complicate the installation if you don’t have one. Not sure what a C-wire is? Start here.
From there, I move on to the app. Every smart thermostat has one. I download the app and create an account if I don’t already have one. Then I configure the thermostat following the steps in the app. This usually means connecting to the local Wi-Fi network, giving your thermostat a name like “Hallway” or “Bedroom” and then you can start using your thermostat.
How well does the app work? Is it easy to navigate to the thermostat settings you need? Is it simple to create a schedule or enable geofencing? This factors into the thermostat’s usability score, along with how simple the thermostat hardware itself is to control manually.
I also test smart home integration, especially voice-enabled systems you can access through voice assistants like Alexa, Google Assistant or Siri. Most connected thermostats have compatibility with at least one voice assistant and some, like the Ecobee3 Lite and Ecobee Smart Thermostat, work with all three. Do the voice commands flow naturally, like they would in an actual conversation? Did the thermostat actually adjust the temperature — heating and cooling — according to your commands?
All of these things determine a smart thermostat’s overall score and how likely I am to recommend it.