Smart thermostats do more than manage your home's heating and cooling. 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. Here's a list of smart thermostats we've tested recently:

Chris Monroe/CNET E D I T O R S ’ C H O I C E 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. Read our Ecobee SmartThermostat with Voice Control review.

Now playing: Watch this: Ecobee's new thermostat is part Alexa speaker

Chris Monroe/CNET The Honeywell Lyric T5 costs less than $150, making it our choice for the best smart thermostat pick for those on a budget. I know that isn't exactly affordable. But it's a solid price tag for a Wi-Fi thermostat. Many models, including the Nest Learning Thermostat and the Ecobee4, cost $249. This makes the T5 a great "budget" option that works with Amazon Alexa, Google Assistant and Siri (via Apple's HomeKit). Read our Honeywell Lyric T5 Wi-Fi Thermostat review.

Chris Monroe/CNET 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. Read our Resideo Honeywell Home T9 Smart Thermostat review.

Chris Monroe/CNET E D I T O R S ’ C H O I C E The Ecobee Smart Thermostat comes with Amazon's Alexa built in. Ask the speaker for the temperature, current weather forecast, to tell you a joke -- and to adjust the air conditioning of your smart thermostat, all without needing a separate Alexa speaker. This Wi-Fi programmable thermostat also offers mobile app integration with Google Assistant and Siri, so if you have a Google-Assistant-enabled smart speaker or a HomePod, you can control it with Google Assistant and Siri commands. Read our Ecobee SmartThermostat with Voice Control review.

Tyler Lizenby/CNET I hold that the $249 Nest Learning Thermostat is still the best-looking smart thermostat out there. Its rounded design harkens back to old-school thermostats, but the device has a modern look that fits in with nearly any home decor. The $169 Nest Thermostat E looks nice too, but it has more plastic components that aren't as appealing as the Learning Thermostat's stainless steel. Read our Nest Learning Thermostat Third Generation review.

Chris Monroe/CNET E D I T O R S ’ C H O I C E The Ecobee mobile app setup is straightforward and easy to install and navigate. That sounds simple enough, but so many apps make it tough to find the specific setting or feature you're looking for. Not so with Ecobee's smartphone app. And that's important because the mobile app is one of the main ways to interact with your Wi-Fi thermostat when you aren't standing directly in front of it (aside from using a voice command). Read our Ecobee SmartThermostat with Voice Control review.

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 baseplate 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.

More smart home buying guides