You know it’s long past time to consider adding a smart thermostat to your home’s repertoire–or upgrading the one you already have. Installing one will have an outsize impact not only how comfortable you are in your home, but also on your household budget. Heating and cooling your home accounts for nearly half of the average home’s utility bills, according to the U.S. Department of Energy.
A programmable thermostat can help reduce those costs by turning your HVAC system on when you anticipate being home, and off when you don’t think you’ll need indoor climate control. A smart thermostat goes far beyond relying on a simple schedule. It will enable you to create more sophisticated schedules for every day of the week, and give you complete control over your HVAC system, even when you’re away from home. We continually test and evaluate smart thermostats and can help you find the right one for your home.
Updated May 17, 2022 to add a link to Ecobee Smart Thermostat Premium review. The successor to our previous top pick in this category, Ecobee’s latest slips easily into the same spot. It’s a spectacular smart home product.
Best smart thermostat for every budget and HVAC system type
Ecobee Smart Thermostat Premium — Best smart thermostat overall
Pros
- Beautiful industrial design
- Broad compatibility with other smart home ecosystems
- Outstanding user interface, both in the excellent app and on the device itself
- Radar-based motion detection, plus support for remote temperature/motion sensors
- Supremely easy to install and configure
Cons
- Siri support requires the presence of an Apple HomePod or HomePod mini
- Air quality sensor won't trigger your HVAC system's fan to circulate air
- Pricey
Nest usually gets all the attention—and the company deserves credit for shaking up a once sleepy market—but Ecobee’s latest smart thermostat is the best you can buy today. The Ecobee Smart Thermostat Premium is beyond best in class, it’s everything a modern smart home device should be: Spectacularly useful on its own, and capable of working with every other important smart home platform on the market today. We are curious why Ecobee included an air quality sensor, but didn’t enable it to cycle your HVAC system’s ventilation fan to turn on, and it’s annoying that you must also have an Apple HomePod or HomePod mini in order to use it as a Siri smart speaker (Alexa is your other choice), but that’s about the only fault we can find with it.
Nest Learning Thermostat (3rd generation) — Best smart thermostat overall, runner-up
Pros
- The best algorithms on the market
- Excellent interface and easy set-up
- Top-notch industrial design
Cons
- Overly reliant on its built-in motion sensor (or your buying other Nest products)
- Nest doesn’t like geofencing, so it thinks you shouldn’t either
- Incompatible with Apple's HomeKit ecosystem
The Nest is still the best for users who don’t want to think about their thermostat, but don’t count Nest out of the thermostat game. The Google division has worked harder than anyone to build out a comprehensive smart home ecosystem with its own products—the Nest Cam security camera series and the Nest Protect smoke and carbon-monoxide detectors. The recent addition of the Nest Temperature Sensor makes this device even smarter.
Amazon Smart Thermostat — Best budget-priced smart thermostat
Pros
- Automatically learns your heating and cooling needs
- Can be controlled with Alexa voice commands
- Broadly compatible with 24V HVAC systems
Cons
- Not compatible with Google Assistant
- Not compatible with Apple HomeKit
- Power adapter kit costs extra if your HVAC system doesn’t have a C-wire
Amazon wins this category with the least expensive, most sophisticated smart thermostat in its price range, and that goes double for households that revolve around Amazon’s Alexa, since it’s not compatible with Google Assistant or Apple HomeKit. But it does support a broad array of HVAC systems and it will learn your comings and goings over time to save energy by not heating and cooling an empty home.
Nest Thermostat — Best budget-priced smart thermostat, runner-up
Pros
- Attractive industrial design, available in four colors
- Very easy to install, program, and use
- Monitors your HVAC system for potential problems
- Energy Star certified
Cons
- No support for remote room sensors
- Not suited to more complex HVAC systems
- Backplate for covering holes from previous installations is a $15 option
It’s hard to beat the Nest team when it comes to attractive industrial design, and the Nest Thermostat is an elegant device if you don’t need to support more sophisticated HVAC systems or you don’t care that it doesn’t support remote sensors that can eliminate hot and cold spots in your home.
Mysa Smart Thermostat — Best smart thermostat for high-voltage heaters
Pros
- Wi-Fi adapter is built in, no additional-cost bridge required
- Compatible with Amazon Alexa, Google Assistant, and Apple HomeKit
- Easy-to-use mobile app
- Stylish industrial design
Cons
- Minimalist design limits the amount of information the device itself can display
- Not compatible with Samsung SmartThings (compatibility was added after our review)
- Wiring can seem confusing compared to the thermostat you’re replacing
These types of thermostats are designed for baseboard, radiant, fan-forced convector, and similar types of heaters, as opposed to the more common central HVAC systems. As such, there are far fewer choices in this category. So far, the Mysa Smart Thermostat is our top pick, due to its elegant industrial design and its broad support for other smart home devices, including Amazon Alexa, Google Assistant, and Apple HomeKit.
Sensibo Air — Best controller for a stand-alone air conditioner
Pros
- Secondary sensor that monitors motion as well as temperature and humidity
- Lots of air-conditioner control options
- Compatible with many brands of stand-alone air conditioners
Cons
- It will take a lot of energy savings to recoup the price
- Single-band (2.4GHz) Wi-Fi adapter
- No onboard controls or UI on the main unit
If you don’t have a central HVAC system, or if your supplement one with one or more stand-alone air conditioners, the Sensibo Air will make those units smarter and more efficient. It’s expensive, but very much worth the cash.
Cielo Breez Plus — Best controller for a stand-alone air conditioner, runner-up
Pros
- Incredibly easy to set up and use
- Tracks humidity as well as temperature
- Broad compatibility with various models of air conditioners
Cons
- Fragile build quality
- Unattractive industrial design
- Scheduling section of display is difficult to read
While this isn’t the most attractive air-conditioner controller we’ve seen, it is the most versatile and the easiest to set up and use. It’s also compatible with more air conditioner models than its competitors.
What to look for when shopping for a smart thermostat
C-wire requirement Most smart thermostats require more electrical power than a set of batteries can provide. Fortunately, they don’t require so much power than they need to be plugged into the wall. They rely instead on low-voltage power provided by your HVAC system. Many smart thermostats require the presence of a dedicated C (common) wire for this purpose, while others can siphon electricity from another source, typically the R (power) wire. But the latter practice is known to cause problems with some HVAC systems, including permanent damage. If you pull out your existing thermostat to install a smart model and find no C wire connected to it, look inside the wall to see if there’s one that hasn’t been connected. If there’s no C wire, our advice is to have one installed. Some smart thermostats comes with power adapter kits that can be installed if you don’t have a C wire and don’t want to pay to have one installed.
Ease of installation A thermostat shouldn’t be difficult to install, even if you’re only moderately handy. The manufacturer should provide comprehensive, yet easy-to-understand instructions with plenty of photographs or illustrations to guide you through the process. The thermostat itself should be clearly indicate which wires go where, and most companies provide labels that you can attach to the wires coming out of the wall as you disconnect and remove your old model. The wires themselves should be color coded, but a good practice is to photograph your old thermostat for reference before you take it down.
Geofencing This feature uses the thermostat’s app and your smartphone’s GPS chip to establish a perimeter around your home. When you leave the perimeter, you presumably no longer need to heat and cool your home, or you can at least have the thermostat adjust the temperature so that it’s not running unnecessarily. When you cross the perimeter again as you come home, your HVAC system can kick into action so your house is comfortable when you walk in the door.
High-voltage heater support Most smart thermostats are designed to work with central HVAC systems. If your home is heated by high-voltage heaters (baseboard, radiant, and fan-forced convector, for example), you’ll need a thermostat that’s specifically designed to work with that type of heater.
Remote Access Remote access enables you to control your thermostat from afar, so that you can check in and adjust the temperature from wherever you have a connection to the internet.
Sensors Geofencing is great—provided everyone who lives in the home has a smartphone. Motion and proximity sensors offer an alternative means of determining if your home is occupied and therefor in need of climate control. The original Nest thermostat was often criticized for relying too much on its motion sensor. If no one walked past it often enough, it would decide that the house was empty and it would stop heating or cooling. Some smart thermostats can also tap into door and window sensors as well as the motion sensors for your home security system. And proximity sensors on the thermostat itself can trigger a thermostat’s display to turn on when you walk past it, making the screens a handy feature in their own right, even if for no other reason than providing a nighttime pathway light.
Smart-home system integration Every smart thermostat comes with an app so you can control it with your smartphone or tablet, but the best models can also be integrated with other smart-home devices and broader smart-home systems. This can range from being able to adjust the temperature with a voice command via an Amazon Echo or Google Home digital assistant, to linking to your smoke detector so that your fan automatically turns off when fire is detected, preventing smoke from being circulated throughout your home. Other options to consider include IFTTT and Stringify support, Apple HomeKit compatibility, smart-vent connectivity, and tie-ins with home security systems.
System complexity Each of the thermostats we tested support multi-stage heating, ventilation, and air conditioning (HVAC) systems, as well as heat pump systems. If your home is divided into zones that are heated and cooled independently of each other, you’ll probably need one thermostat for each zone. A single app should be able to control multiple zones.
User interface Long gone are the days when a thermostat’s user interface consisted of numbers on a dial. The more sophisticated a device becomes, the more difficult it can be to learn to use. The last thing you want to be doing is staring at inscrutable hieroglyphics on the wall when all you really want is to be warmer or cooler. A smart thermostat should convey important information at a glance and should easily adapt to your specific needs.
How we test smart thermostats
We install thermostats in a single-family home with a conventional HVAC system and use each one for a week or more to determine how effective it is at maintaining a comfortable environment. The home’s existing thermostat was wired with G, R, W, and Y wires. There was also a C wire in the wall that was connected to the furnace, but that had not been previously used.
While there is no regulated standard for color-coding HVAC wires, industry practice has the G wire connecting the thermostat to the fan. This wire is typically green. The R wire, typically red, is for power. Some systems have separate power wires for heating and cooling and are labeled RH and RC respectively. The typically white W wire is for auxiliary heat; i.e., a second source of heat. The Y wire, which is typically yellow, connects the thermostat to your air conditioner. Finally, the C or “common” wire is used to carry power and is typically blue (think cerulean if you need a mnemonic).
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