The best smart thermostats of 2020

Smart thermostats do more than automate a fixed heating and cooling climate-control schedule. These app-enabled smart home devices make it possible to adjust your thermostat from your smartphone whether you're on the couch, at the grocery store or on vacation -- anywhere your smartphone is connected to a cellular or a Wi-Fi network. Many of these devices also work with Alexa, Google Assistant and Siri now too, giving you yet another way to adjust your thermostat settings with remote access. 

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. Other systems 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 (i.e., compatible with Apple HomeKit) and, of course, thermostats that measure your energy usage so that your home can me more energy efficient.

Even better, these options offer way more than a programmable thermostat -- you want a learning thermostat that gets better at regulating your temperature just the way you like it the longer you have it.

To accompany these modern features, many connected heating and cooling systems boast innovative designs. From a rounded shape to a responsive touchscreen, thermostats look a lot different than they used to.

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. Here's a list of smart thermostats we've tested recently:

1. Ecobee3 Lite
2. Ecobee SmartThermostat
3. Emerson Sensi
4. Emerson Sensi Touch
5. Honeywell Lyric
6. Honeywell Lyric T5
7. Johnson Controls GLAS
8. Lux Geo
9. Lux Kono
10. Nest Learning Thermostat
11. Nest Thermostat E
12. Resideo Honeywell Home T9

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:

1. Turn off power to your thermostat at the circuit breaker
2. Remove the old thermostat
3. Install the thermostat's baseplate with the included screws
4. Attach the wires to the wire terminals 
5. Snap on the faceplate
6. 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 SmartThermostat, 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.