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We’ve added the GE Cync Smart Thermostat to What to look forward to.
A smart thermostat does the thinking you don’t want to do. It can learn your schedule, turn itself down when nobody is home, and balance temperatures around your home to make you comfier while using less energy (talk about win-win). Our extensive testing shows that the Google Nest Learning Thermostat is the best smart thermostat because it manages your home with the least amount of input, it’s simple to use, and it has the best design of all the thermostats we’ve tested.
Smart thermostats aren’t universal, so may not support all the features of your HVAC. To be sure, consult the compatibility checker on a brand’s website.
To address areas in your home that are under heated or cooled, choose a thermostat that works with tiny remote temperature sensors.
Smart thermostats are set up with a smartphone app, but most models can also be controlled using Amazon Alexa, Apple HomeKit, or Google Assistant.
To maximize energy efficiency, enable geolocation, which lets the thermostat turn off the HVAC when you aren’t home, and back on before you return.
Nest’s most-advanced smart thermostat features a larger, crisper, and more useful display and wide compatibility with HVAC systems.
Compatibility: Amazon Alexa, Google Home, SmartThings
The Google Nest Learning Thermostat (third generation) learns your heating and cooling preferences and then intelligently creates an optimized Schedule to maximize efficiency, so you don’t have to program it yourself.
It installs easily, it’s compatible with most systems, and it works with Nest Temperature Sensors, which you place in trouble spots to better keep all of your rooms comfortable. The hardware looks and feels superb, with an excellent tactile control wheel and a beautiful screen that doubles as a time or weather clock. It also comes in seven finishes to provide options for working with your home decor. Some homeowners may have to deal with wiring and power issues in order to use the Nest with their HVAC system (see What to know before you buy).
Ecobee’s SmartThermostat comes with smarter sensors, a sleek glass touchscreen, and a decent built-in smart speaker. It works with most smart-home platforms, including Apple HomeKit and Amazon Alexa.
Compatibility: Amazon Alexa, Apple HomeKit, Google Home, SmartThings
With a simple Alexa voice command, Ecobee’s SmartThermostat with Voice Control can play music, relay the news, and control your home’s smart lights—along with adjusting the heat and air conditioning. It also works with remote sensors, which you can place in rooms that are too hot or cold. The temperature and occupancy detectors in the sensors let the Ecobee tweak its settings to ensure that every location throughout your home is comfy, rather than just the spot where the thermostat is installed. (One sensor comes with the unit, and you can add up to 32.)
Because it has Alexa built in, you don’t need a separate Echo speaker to control it by voice, and if Alexa isn’t your smart-assistant choice, this model also works with Google Assistant and Apple HomeKit and Siri with the use of separate speakers. While the Ecobee doesn’t have the level of intelligence of the Nest Learning Thermostat for automatically figuring out a Schedule, it’s a good option if you have problems with cold spots in your home.
This Honeywell model can’t auto-create a custom Schedule and isn’t as simple to use as other picks, but it works well, doesn’t cost as much, and supports Alexa and HomeKit.
*At the time of publishing, the price was $110.
Compatibility: Amazon Alexa, Apple HomeKit
The Honeywell Home T5 Smart Thermostat is a less-expensive smart thermostat that still offers most of the important features of our other picks. Although it can’t sense your presence or automatically determine a Schedule, its built-in geofencing feature works very well and allows for useful interactions with other smart-home devices, such as triggering lights when you arrive home or leave. The T5 is compatible with Apple HomeKit and Siri, Google Assistant, and Amazon Alexa.
A pricey but practically perfect option for adding smart controls to electric baseboard heaters, Mysa uses scheduling, geofencing, and a smart eco mode to save you money while imperceptibly using less energy.
The Mysa Smart Thermostat will make your “dumb” and inefficient electric baseboard heating far more cost-effective. It’s our only pick in what is an admittedly limited field—it works with 110-volt electrical heating sources—and we like its clean, modern design, as well as the fact that it doesn’t require a separate hub and it works with all the major smart-home systems (Alexa, Google Assistant, HomeKit, and SmartThings). Mysa uses geolocation and artificial intelligence alongside scheduling and zoning to heat your home efficiently and save energy while keeping you comfortable.
Nest’s most-advanced smart thermostat features a larger, crisper, and more useful display and wide compatibility with HVAC systems.
Ecobee’s SmartThermostat comes with smarter sensors, a sleek glass touchscreen, and a decent built-in smart speaker. It works with most smart-home platforms, including Apple HomeKit and Amazon Alexa.
This Honeywell model can’t auto-create a custom Schedule and isn’t as simple to use as other picks, but it works well, doesn’t cost as much, and supports Alexa and HomeKit.
*At the time of publishing, the price was $110.
A pricey but practically perfect option for adding smart controls to electric baseboard heaters, Mysa uses scheduling, geofencing, and a smart eco mode to save you money while imperceptibly using less energy.
I’ve spent the past eight years testing smart thermostats in my home, installing and uninstalling more than two dozen of these climate controllers. As a journalist for 20 years, I’ve covered smart-home technology for Wirecutter as well as for Dwell Magazine, U.S. News & World Report, BBC Science Focus, Wired UK, and The Ambient. I write extensively on how to save energy around the home and how a smart home can help promote a sustainable lifestyle, and I also test smart smoke alarms, smart garage-door controllers, smart sensors, and smart sprinkler controllers for Wirecutter.
A smart thermostat is a good investment for any homeowner who is looking to trim their energy usage (and utility bills) or who wants a convenient way to control their home’s climate—whether that’s from the couch or the other side of the world. By intelligently managing your heating and cooling, a smart thermostat can dramatically increase the efficiency of your home’s climate-control system: According to the EPA, many homeowners can expect to save as much as 30% (PDF) on their annual heating and cooling bills by using a smart thermostat compared with using a non-programmable thermostat.
The best smart thermostats can also help reduce energy usage for the good of the planet. If every American household were to install a smart thermostat, the energy savings would be equivalent to 1.2 million fewer vehicles on the road, according to Energy Star, which started rating smart thermostats in 2017. Because of those dramatic savings, energy companies frequently offer rebates and incentives for replacing a traditional thermostat with a smart one.
Most smart thermostats integrate well with a home’s other smart devices, and all of the models we tested work with one or more smart-home platforms, including Amazon’s Alexa, Google Assistant, and Apple’s HomeKit and Siri, as well as with smart-home hubs such as Samsung’s SmartThings. That support provides the novelty of using voice control to adjust your home’s temperature, as well as automated ways to optimize the efficiency of your system.
For example, you can have your thermostat lower the temperature when you lock your front door or start warming the house when you arrive home and open the garage. These smart-home ecosystems are continually growing, so the interactions your thermostat is capable of are growing as well (though sometimes only with the purchase of additional hardware).
If you have an older HVAC system, your home may lack the wiring to support a smart thermostat, most of which require a common or “C” wire to provide power. Although all the models we recommend are easily installed by a homeowner, if you lack a C wire, the Nest model is your best option, as it doesn’t always require one depending on your system. For more on this topic, see What to know before you buy.
There are dozens of “smart thermostats” for your home. But a large number of those purporting to be smart merely have Wi-Fi connectivity, which simply gives you remote control via voice or an app—handy but not groundbreaking. We skipped any that didn’t also include other smart features, such as geofencing or sensors. To further narrow down our list of test models, we identified the five most important features to look for when picking the best smart thermostat. In our informed opinion, a worthy model should do the following:
You should expect to spend between $80 and $250 on a smart thermostat. Lower-end models have fewer features—paying less than $80 buys you a basic Wi-Fi thermostat you can control remotely, but no smart functions. A pricier thermostat works with more systems and uses higher-quality materials. Options that cost more than $250 are overkill or are specific to particular HVAC systems.
We elected not to consider branded models from HVAC manufacturers that weren’t compatible with other systems or were available only through dealers, as they won’t work for most people. (If you are having a new HVAC system installed, however, considering a branded model may be worthwhile to get the most out of your system.)
We installed each thermostat ourselves in a 2,200-square-foot, two-story South Carolina home and ran it continuously for at least three to 10 days of routine operation, in some cases up to two years.
The home has a two-zone electric HVAC system, operating a heat pump (not a furnace) with two heating stages. During our testing, we paid special attention to the setup and control of each thermostat both directly and via the companion app, the thermostat’s ability to integrate with other smart gear, and whether it saved energy and money. (For testing of the Amazon Smart Thermostat, we have only tested it so far using heat in a three-story brick rowhouse with radiant heating.)
Wirecutter takes security and privacy issues seriously, and to help you understand which data the companies you are bringing into your home may be taking out with them, we’ve compiled this table to answer some of the most common questions people have regarding privacy and security. We reached out to the companies that produce our top picks and asked them to respond to an extensive questionnaire to confirm their positions on issues that should be of primary concern for any potential buyer. Here is what we think you should consider before making a purchase.
Yes, but it is optional.
Nest’s most-advanced smart thermostat features a larger, crisper, and more useful display and wide compatibility with HVAC systems.
The Google Nest Learning Thermostat (third generation) is the simplest, smartest, most energy-efficient smart thermostat you can buy today. Versions of it have been our top pick or upgrade pick since we started testing smart thermostats, and despite a serious uptick in competition, the Nest thermostat remains the best.
Its standout feature is its success in automating climate control of your home with little to no input from you, other than a week of training. It intelligently learns how you like your environment and adapts to how your home heats and cools, saving you money while keeping you cozy without your having to do a thing.
This learning mode, combined with a simple user interface, a superb design and build, and optional room sensors, makes the Nest model an easy choice as our top pick (Its equally good but less expensive sibling, the Nest E, is now available only via professional installation through heating and air companies, and the also-cheaper Nest Thermostat is a very stripped down version, lacking a lot of the features we like about the Nest system.)
Installation is straightforward, as long as your system is compatible and has a C wire for power. (Although the Nest does not require a C wire to operate in most cases, proceed with caution and read our section on C wires for more on this topic.)
Once you’ve installed the Nest, setting it up is simple. The device prompts you to choose your “eco temperatures”—the setpoint when you’re away—as well as your preferred “home temperatures,” the warmest and coolest you want the house to be when you’re home. You can then connect it to Wi-Fi and the Nest app for remote control—though if you prefer to keep your thermostat offline, you can opt to use it without internet access like a regular thermostat.
To select your preferred temperature throughout the day, you turn the metal dial or adjust the thermostat via the app. Over the course of a week or so, the Nest thermostat gathers that information, combining it with presence sensing via its built-in occupancy sensor (and those of other compatible Nest devices you may have, such as wired Nest Protect smoke alarms or Nest Detect sensors) and your smartphone’s location (if you allow it) to automatically generate a heating or cooling Schedule for you. If you prefer, you can opt to create your own Schedule for the thermostat by using the Nest app, or you can simply tweak the one that the Nest thermostat creates.
The Nest Learning Thermostat has a beautiful, high-quality build that feels like it will last a very long time, and the design is intuitive and easy to use. Just turn the tactile metal outer ring, which feels substantial and glides effortlessly, left or right to adjust the temperature down or up, respectively. Pressing forward on the dial lets you make selections.
The display goes dark when not in use and then lights up to show you the current setpoints and ambient temperature when you approach. It turns red when it’s heating and blue when it’s cooling, giving you a clear visual cue as to what your system is doing. A feature called Farsight turns the screen into a clock that displays the time, weather, or indoor temperature and is viewable from a distance, giving your thermostat some extra function.
We found that once the Nest had figured out our household’s patterns, we rarely, if ever, had to touch the device or adjust the temperature remotely (see Flaws but not dealbreakers for an instance when the Nest can get it wrong). This unique learning feature is the primary reason we have continued to choose a Nest model as our top smart thermostat.
An HVAC monitoring feature detects and notifies you of any problem with your system, such as a furnace shutdown or extended heating or cooling times. We had some experience with this feature in our testing of the more basic Nest Thermostat (See Other smart thermostats we like).
Another essential smart feature of the Nest is its Eco Mode, which uses a combination of presence sensing and geofencing to determine when the house is empty and then tells the thermostat to keep temperatures within an energy-saving range. When it senses you’re home or coming home, based on your habits and the location of your smartphone, it returns to its normal Schedule.
The Nest thermostat also saves energy by employing machine-learning artificial intelligence that measures how long it takes for your home to heat or cool based on outside temperatures and then optimizes your Schedule so that it comes on at just the right time without over- or underheating or over- or undercooling. For example, if the Nest recognizes that it’s colder today than it was yesterday, the thermostat will start heating a bit earlier to hit your target temperature by 7 a.m.
Similarly, the Cool to Dry and Airwave features focus on reducing humidity and using your HVAC’s fan to eke out every last bit of cool in your system when the AC turns off, once again helping to save energy and money. Over time those little tweaks here and there can boost your system’s efficiency. In our long-term testing, we found that these two features combined caused our system’s fan to run almost continuously—largely, we think, because our test house is in the South and high humidity is a constant battle there. However, an always-running fan can become a nuisance noise-wise, so we ended up turning these features off.
We specifically evaluated the energy-usage reporting the Nest offers and looked at how that information could help you save money. The Nest offers a 10-day history in the app and online that shows you when the system was set automatically or manually and to what temperature. This information is useful for determining how your system has been performing and whether Eco Mode has been activating, but it isn’t a deep dive suitable for micro-managing your energy use like the reporting Ecobee offers. You also receive a monthly energy report in your inbox, but this is mostly fluff and advertising.
The most useful insight the Nest thermostat offers for energy savings is the green leaf that appears on the device when you set or are running an energy-saving temperature (based on your heating and cooling history and Nest’s data). This type of visual reward is highly motivating and, combined with the monthly report you get showing how you compare to other “Nesters” in your area, is enough to add a bit of healthy competition to your energy-saving efforts.
Although the Nest thermostat works very well on its own, if you have a home with hot or cool spots, you can pair it with the optional Nest Temperature Sensors, $40 white mini-pucks you place in different rooms to better balance the temperatures throughout your home—thus solving a common problem with many older homes.
You can pair up to 10 sensors with one thermostat and set them on a Schedule in the Nest app that targets the rooms the sensors are in at a certain time of day. For example, we tested three sensors and had the thermostat target the kitchen in the morning, the living room during the day, and the dining room in the evening. We really liked this feature and found that it worked well for a household with predictable routines. Having to set precise times was a bit restrictive, though, and we found that the occupancy sensors on the Ecobee and Honeywell Home T9 sensors, which can trigger the thermostat based on your presence, were a better option in this regard.
You can also control your thermostat with the Nest app, the Nest web portal, or a smart-home platform like Amazon Alexa, Samsung SmartThings, or Google Home (it’s not Apple HomeKit compatible). You can also control it with your voice by connecting it to Google Assistant or Alexa.
The Nest app is really good; it displays the automatically generated Schedule, and it allows you to make temperature adjustments, switch settings and climate modes, and view a 10-day history. If you have other Nest devices, such as cameras or smoke alarms, the app consolidates them all into a single view, which is convenient.
But the Nest app is apparently being phased out, as Google, which owns Nest, has moved a lot of functionality into its Home app, and the newer budget Nest Thermostat doesn’t work with the Nest app. For now, you still need to use the Nest app to handle setup, manage the sensors, adjust your schedule, and see your history, but the Google Home app now has a Home/Away feature that works with the Nest thermostat (or any compatible thermostat) and is a convenient way to manage your climate control and your smart home together. When the feature is enabled, you can have your thermostat set itself to its Away mode when you leave and Home mode when you return. It can also tell compatible smart-home devices, such as lights, plugs, and cameras, to adjust. The Google Home app uses the thermostat’s presence sensor, your phone, and those of any connected family members to determine if you’re home or away.
In our testing, this worked reliably and speedily, and it reacted quicker than the Nest app’s similar function. When we walked in the door, our Philips Hue lights turned on, our Arlo cameras turned off, and the thermostat switched to Home almost instantly. When we left, the reverse happened within 30 minutes of our absence—the quickest any thermostat that doesn’t rely solely on phone geolocation has done so in our eight years of testing smart thermostats.
Another feature we really like is that the Nest can automatically shut down your HVAC system when a connected Nest Protect smoke alarm detects smoke or fire. It’s a feature few other smart thermostats offer: Ecobee can do it if you buy First Alert’s Onelink smoke alarms and connect them to HomeKit; if you have a Ring Alarm system with a Smoke Alarm Listener, you can manually create an Alexa Routine to do the same thing, but Nest’s integration is the simplest to set up and use.
The Nest Learning Thermostat is very expensive. We won’t say it’s overpriced, as the hardware is top quality and should last for years, especially compared with the cheaper, plastic offerings of the competition. But $250 is a lot when you consider the thermostat doesn’t come with any remote sensors or double as a smart speaker, as the similarly priced Ecobee does.
We’ve seen owner reports of Nest Learning Thermostats doing crazy things, such as cooling a home to 50 °F on a cold winter’s morning. In our experience, problems can crop up because the system gets confused about which temperature you want. We had this happen when one unit created an automatic Schedule for the upstairs zone to heat to 81 °F mid-morning and then to 66 °F in the evening. It occurred during a seasonal change, and the temperature setpoint for the thermostat during the day had been at 81 °F cool to save energy; the Nest translated that to 81 °F heat when we switched the Mode from cool to heat. To fix the issue, we deleted the Schedule the Nest had set and told it to relearn, which it did much more effectively the second time. If you run into similar issues, we recommend resetting your automatic Schedule at the start of a new season to let the thermostat learn your new pattern.
The Nest Temperature Sensors are one-trick ponies: They only measure temperature—there’s no presence or motion sensing as you get with Ecobee sensors, or humidity measurement as you get with the Honeywell Home T9 system. We wish they did more so that you could, for instance, use motion to enable a feature like Ecobee’s Follow Me, which adjusts your thermostat to where you are in the house, instead of having to program Schedules for your sensors. We also think Google should include one sensor with the Nest thermostat, as Ecobee does for its model.
Ecobee’s SmartThermostat comes with smarter sensors, a sleek glass touchscreen, and a decent built-in smart speaker. It works with most smart-home platforms, including Apple HomeKit and Amazon Alexa.
If you want a thermostat you can put on a wall and forget, Nest is best. But if you want deep control over every change your thermostat makes, Ecobee is the better choice.
The Ecobee SmartThermostat with Voice Control is a complex piece of equipment that can do nearly everything you might want a smart thermostat to do; it also works with every major smart-home system (including Apple HomeKit), and it even doubles as an Alexa smart speaker. However, it has a more difficult learning curve, needs a C wire for power, and requires you to do a bit of tinkering to get the most out of its powerful capabilities.
The Ecobee SmartThermostat is a well-designed device that looks good on a wall. You control it with a glass touchscreen that’s responsive and easy to use. It has small touchpoints, however, which are tricky for those with larger fingers to navigate precisely (a 6-foot-4 member of our household has a tough time with it).
Monitoring and controlling the thermostat remotely using Ecobee’s excellent app or web interface is also easy and intuitive, as the interface is identical across all three platforms. The website is where you’ll find extensive insights and real-time updates about your energy usage and thermostat setpoints, something Nest does not offer.
Our favorite feature of Ecobee’s system is its SmartSensor room sensors. These small, square devices have sleek rounded corners and a variety of mounting options so you can easily place them around your house to monitor temperature and occupancy. By keeping tabs on two or more areas this way, you can choose to have your system prioritize one sensor over the others or average the temperatures between them. This arrangement solves the age-old heating and cooling problem where one room is toasty and warm while another feels like a refrigerator (or vice versa in the summer). The thermostat comes with one sensor, and you can add up to 32.
(Ecobee has also released the $80-per-pair SmartSensors for Doors and Windows, contact sensors for doors and windows that shut down your HVAC system whenever an entrance is opened or shut. However, they work only as part of Ecobee’s new home-security platform, which requires a $5 monthly subscription for its Haven monitoring service.)
The Ecobee thermostat is compatible with the same number of HVAC systems as the Nest, including those systems with humidifiers, dehumidifiers, and ventilators (you can check its compatibility with your system). It does require a C wire, but a power-extender kit and detailed instructions for how to wire it to your HVAC system are included in the box if you don’t have one. It is also Energy Star rated, potentially qualifying you for a rebate.
Installation is similar to that of the Nest and straightforward, although if you have a complicated HVAC system you may want to enlist the help of an expert. Including pairing four sensors, connecting to Wi-Fi, and setting up three smart-home system integrations, installation took us about an hour. If you have to wire in the power extender kit, factor in an extra two hours or hiring an electrician.
This is the only thermostat to feature a built-in smart speaker, and the audio quality and microphone responsiveness are on a par with those of the third-gen Amazon Echo Dot in quality. All the standard Echo speaker features are here, including Alexa Calling, Messaging, and Drop In, so you can use your thermostat as you would an old-school intercom system. It doesn’t work with Alexa multi-room music.
In use, the Ecobee thermostat offers you two main ways to control your climate:
These systems—which Ecobee has re-branded Eco+—work together to balance comfort and energy use, and in our testing the thermostat did a very good job of maintaining the home at a comfortable temperature while not using excessive energy when we were home.
When we were away, however, it took too long to automatically adjust to Away Mode, and then to recognize when we returned home, even with geofencing options turned on. For example, when we arrived home while the Schedule was set to Away, it took over 30 minutes to switch, by which time we had walked over to the thermostat and changed it. Conversely, when we left during a Home period, it sometimes wouldn’t switch over to Away at all, even after the hour waiting period Ecobee says is standard.
To get the greatest energy savings, you need to either manually change the mode to Home or Away status (on the touchscreen or in the app) or set up other smart-home integrations to do that for you (more on those later). But a word of warning here: If you deviate from the Schedule or presence-sensing setup, the system goes into an indefinite hold and can cause problems such as your system running overnight when you thought it would revert to your Sleep setting (this happened in our testing). You can fix this by changing the default hold action in the web settings from “Indefinite” to either a timed delay or “Until the next scheduled activity.”
If you want to use your Ecobee thermostat with a smart-home system, this problem gets trickier: If you use Alexa, HomeKit, or another external system to change the temperature, the thermostat will hold at that setpoint until you manually change it. Our advice is to stick with one system (either Ecobee’s platform itself, or Alexa, HomeKit, or Google Assistant) and just use that. If you bounce between them, you’ll end up confusing the Ecobee and possibly using more energy than you would have without a smart thermostat.
A big selling point of the Ecobee thermostat is that it's compatible with all those different smart-home systems. Because Alexa is built into the device, you can use your voice to adjust the temperature, ask Alexa which equipment is running, and hear what the temperature is in different rooms. The voice assistant can even set up Vacation Mode for you, and you can plug the thermostat into Alexa’s Routines.
HomeKit integration is a nice feature for Apple users. You can access your thermostat settings directly from your iPhone’s Control Center with a quick swipe, control the Ecobee by voice with Siri, and add it to HomeKit’s Scenes, which are presets you configure between one or more devices and trigger by button or voice—a “Good Morning” Scene, for instance, could turn up the thermostat, turn on the lights, and start the news.
Later this year, Siri will be available as the built-in voice assistant in the Ecobee SmartThermostat, although you’ll also need to have an Apple HomePod Mini for the integration to work.
The Ecobee also works with Samsung’s SmartThings, Google Assistant, and most other smart-home platforms.
Last year, Ecobee pushed a software update to all its thermostats that automatically enabled a feature called Eco+, which the company said was designed to improve energy and cost savings without impacting comfort.
At its most basic, Eco+ is a software upgrade that claims to improve on the existing Home and Away feature, reducing the amount of time the system takes to switch to Away to one hour instead of two (this did not bear out in our testing, as noted above). It also adds four new features, including the suggested Schedule changes we’ve discussed, a Feels Like feature that leverages humidity sensing to help keep your home more comfortable, and Time of Use and Community Energy Savings options that allow you to connect your thermostat to your utility company to take advantage of any rebates or special pricing it might offer.
Although the update occurred automatically, the features have to be set up manually, and if you don’t want any of them you can disable them individually. If you are using just the Ecobee thermostat and app to manage your home’s climate, we recommend keeping the Smart Home and Away feature and Schedule Assistant on. If you’re using a third-party smart-home system to manage the device, however, turn them off.
We have not been able to properly test the Feels Like feature, as we did our testing during the summer in South Carolina, when average humidity hovers around 70% indoors. But the alerts it sent indicating that humidity was high seemed to be a useful addition. Similarly, our test household’s utility provider does not participate in any of the connected thermostat programs, so we can’t provide any perspective on that. But if yours does, we advise talking with your utility company first to understand exactly how the program might impact you before enabling anything through the thermostat.
This Honeywell model can’t auto-create a custom Schedule and isn’t as simple to use as other picks, but it works well, doesn’t cost as much, and supports Alexa and HomeKit.
*At the time of publishing, the price was $110.
The Honeywell Home T5 Smart Thermostat is the least expensive smart thermostat we recommend. Although it can’t sense your presence at home and doesn’t automatically create a Schedule, it offers many of the other major features you might look for in a smart thermostat, including smart scheduling, native geofencing, integration with the major smart-home platforms, and an Energy Star rating. If you are specifically looking for a thermostat to use with Alexa, Google Assistant, or Siri and don’t need more advanced capabilities, the T5 is a good option.
The T5 edged out our previous budget pick (the Ecobee3 Lite, which works with all of the same systems) because it’s less expensive. The T5 is good-looking, if somewhat chunky, consisting of a sleek black box with white fonts on a black screen, like a digital alarm clock. It’s compatible with most 24-volt conventional forced air, heat pump, hot water, and steam heating systems, and it supports two-stage heating and cooling, though not humidifiers and dehumidifiers. To use the T5, your HVAC system must have a C wire; if it doesn't, Honeywell sells another model, the T5+, which includes a power extender kit.
Installation is straightforward, and the device walks you through enabling geofencing and setting the temperature you want for Wake, Home, Away, and Sleep Modes. You use the Honeywell Home companion app to pair the thermostat with HomeKit (if you want to) and to connect the device to Wi-Fi to set up Schedules or enable geofencing. In our initial testing, we encountered issues with the device disconnecting from Wi-Fi, but after a reset we had no further problems. The big, black screen does get dirty quickly, but a “clean screen” option gives you 30 seconds to wipe it down without making your thermostat go haywire.
The screen displays the time and current temperature until you touch it, which in our testing required a surprisingly forceful press (and sometimes more than one). It then displays the time, the target temperature, the current temperature, and a huge array of on-screen buttons, including for plus and minus temperature; Home, Away, and Sleep Modes; the current Mode; and Off, Cool, Heat, Emergency Heat, and Fan. (Resideo, the manufacturer, crammed in quick access to all the buttons to relieve you from having to manually scroll through and select the functions, which is clunky and unintuitive.)
The T5 can use geofencing to trigger changes in the thermostat’s settings by monitoring the location of your smartphone as well as the phones of anyone else in your household (which can cause problems if any of your household members don’t have a smartphone). Based on your location and time of day, it then switches to your Home, Away, or Sleep preset. This function worked well in the downstairs zone of our two-story test home, but we preferred the scheduling option for the upstairs zone. You can’t have a Schedule and geofencing enabled on the same device at the same time, something that’s true of most of the thermostats we tested except, notably, the Nest and Ecobee models.
Setting a Schedule in the Honeywell Home app is straightforward and far simpler than doing so on the device, with its scrolling menus that look like an old-timey Speak & Spell. Choose from “Same Every Day” or “Different on Weekends” to start with, and you get a preset Schedule you can easily adapt to your needs.
A pricey but practically perfect option for adding smart controls to electric baseboard heaters, Mysa uses scheduling, geofencing, and a smart eco mode to save you money while imperceptibly using less energy.
The Mysa Smart Thermostat is a line-voltage smart thermostat, so unlike all the other models we tested, it works with 120- or 240-volt electric heating sources, such as electric baseboard heating. There are limited options for line-voltage smart thermostats, but we recommend the Mysa because it doesn’t require a separate hub to connect to the internet, it has an easy-to-use app, and it has a simple and attractive design with a subtle dot-matrix-like display and capacitive buttons. The Mysa thermostat also has built-in geofencing and works with Alexa, Google Assistant, HomeKit and Siri, SmartThings, and IFTTT.
Baseboard heaters are typically controlled by individual thermostats at each unit—adding smart thermostats brings a huge benefit because it allows you to control all your units at once rather than by hand in every single room. And if you have more than one heater controlled by the same thermostat now, you can wire a single Mysa in its place (provided the total load doesn’t exceed 3,800 watts). You can also put multiple units into zones—upstairs, downstairs, bedrooms, and so on—to adjust them simultaneously in the app as one unit. Aside from offering a huge boost in convenience, the Mysa has the potential to dramatically improve efficiency by intelligently adapting to your energy usage.
The big caveat is that in installing the Mysa system, you need to replace every thermostat, which gets expensive quickly—though that up-front cost could be offset by energy bill savings, since electric baseboard heating is so much less energy-efficient than other systems.
Due to the limitations of our test home, we weren’t able to test the Mysa thermostat on a baseboard heater, but we did rig it up to a dummy unit to test its responsiveness, features, and app control. Installation is simpler than for a Nest or Ecobee model, as it has fewer wires, but you’re dealing with much higher voltage levels, so it’s imperative that you shut off the power before installing.
Once you’ve installed the thermostat, you use the Mysa app to set it up, connecting it directly to your home’s Wi-Fi (2.4 GHz only). The only setting you can adjust directly on the Mysa is temperature, so to tweak other settings you have to use the app. The display shows the ambient temperature by default, and when you press the up or down arrow, it changes the heat settings accordingly and shows the adjusted temperature.
The Mysa thermostat manages your heating in a few different ways. You can use a preset, Energy Star–recommended work-week Schedule or create a customized Schedule by using a wizard. The wizard asks a few simple questions concerning what time you wake up and go to bed, how often you leave the house, and what Sleep, Home, and Away setpoints you prefer. Early Start is an optional setting that learns how long it takes to heat up a given room and then adjusts the Schedule to make everything toasty right on time.
The optional Intelligent Eco Mode (which you can turn off) imperceptibly modulates the temperature by a half-degree to boost your savings over time as it learns how your system works. Because baseboard heat doesn’t rely on blowing air around like furnace heat, your Mysa thermostat can maintain temperatures more efficiently while keeping these tiny changes unnoticeable.
One feature we were able to fully test—and found very reliable—is geolocation. On the Mysa thermostat, it works in tandem with the scheduling (so it works more like the feature on the Ecobee than on the Honeywell), giving you the option to have your regular Schedule resume or pause when you arrive or leave, or to hold a set temperature. It’s a nice way of implementing what we’ve found can be a spotty, often hard-to-use feature when it comes to controlling a home’s climate. Because geolocation relies on your smartphone’s location and not presence sensors, it may not be a good choice if you have family members or visitors who aren’t tied to the Mysa app, or the heat may shut off on them whenever you leave.
We weren’t able to test the Mysa system’s energy-reporting capabilities, but based on a demo we saw it’s capable of providing near real-time reports of electrical usage, as the current runs directly through it. That lets you see exactly how much electricity you're using—as well as exactly how much that energy is costing you, an impressive motivator to put on an extra sweater. You can drill down into the month, week, and day, as well as by the whole system, zone, or individual unit.
The biggest flaw of the Mysa thermostat is its price, since electrical baseboard heating generally requires a thermostat in every room. That means you could need between three and 10 units, for a $420 to $1,400 investment. We are currently testing a new Wi-Fi model from Sinopé that is $20 cheaper (See What to look forward to). Mysa’s clean, minimalist design is attractive, but it does limit the display of on-device details.
We were disappointed that the Mysa thermostat doesn’t let you make across-the-board changes to a Schedule once you’ve set it up—only to individual times and temperatures. So if you want to tweak a daily start time, for example, you have to either manually copy it to every day or delete the whole Schedule and start from scratch.
A few things to know about smart thermostats before you choose one:
A common wire, or C wire, supplies AC current from your furnace to the thermostat to power the screen, among other things, and some homes, especially older ones, may not have that wire (if your current thermostat has just two wires, you don’t have a C wire). Some thermostats, including Nest models, can work in the absence of a C wire by stealing power from other wires. That clever solution can cause serious side effects, according to Bronson Shavitz, an HVAC contractor we spoke with in 2016: He told us that old-school furnaces are generally resilient enough to provide power for devices such as the Nest and Honeywell (Lyric) thermostats, but that the high-tech circuit boards on newer furnace models can be more prone to failure as a result (although newer models are more likely to have a C wire). The expense of replacing a furnace or AC board, plus the cost of professional installation, outweighs the convenience or energy savings of a smart thermostat. Google addresses this problem and what systems are best suited for Nest thermostats on this page.
There are a few other solutions to the C wire conundrum. One option is to have an electrician install one for about $150. Alternatively, Ecobee and Honeywell offer the option of hardwiring a power extender kit to your HVAC system yourself, and some smart thermostats claim to work without one—but you should take that promise with a grain of salt and confirm with a professional if you are unsure.
While some smart thermostats have removable batteries to provide power—the Emerson Sensi and the new Nest Thermostat both use batteries—that only allows the thermostat to work like a standard programmable model. They don’t provide enough power for the thermostat to connect to Wi-Fi to enable the smart features.
Many of our readers are concerned about how the manufacturing, shipping, and normal use of the products we recommend impact the world we all live in. Wirecutter takes that seriously too, which is why we’ve asked the manufacturers of all our picks to answer some basic questions about the materials they use, the life cycle of their products, and related issues that affect their overall sustainability. While our product recommendations are based on the criteria outlined in How We Picked and Tested, we offer this information to supplement the decision of any reader who would want to use environmental impact as a deciding factor in their purchases. We also recognize that due to the complicated nature of the topic, this info is necessarily incomplete and may not paint a full picture of a given product’s overall environmental impact.
Smart thermostats are innately energy-saving devices, especially when they replace traditional, non-programmable thermostats. All of our picks except the Mysa are Energy Star certified by the Environmental Protection Agency (Mysa isn’t included, as line-voltage thermostats aren’t an Energy Star category yet), which means they have been independently verified to provide energy savings. Ecobee says that with its SmartThermostat, users can expect to save up to 26% off their heating and cool bill versus having a thermostat set at a fixed temperature of 72. Mysa also claims 26% savings. Nest claims it can save 10-12% on heating and 15% on cooling (so from 25- 27% on your total annual HVAC bill).
Unlike traditional thermostats, which may last decades, smart ones are essentially small computers and so require periodic software updates to remain compatible and secure. And as a relatively new product category, we don’t yet know what a reasonable lifespan is. Mysa says it estimates a 10-15 years life for its thermostats and says it will continue to support it with updates. Ecobee says its products have an average lifespan of more than 10 years and notes that 2/3rds of its 2014 Ecobee3 models are still in use; for now it plans to support those devices and all newer ones indefinitely. Similarly Nest says that a “significant portion” of the 1st generation thermostats sold in 2011 and 2012 are still in use, and that while it continues to offer critical security updates to all its devices it only commits to providing updates for 5 years. Honeywell did not provide a lifespan estimate.
None of the thermostats have user-serviceable parts, which isn’t a surprise—they’re fully electronic—and only the Nest thermostat contains a battery, which isn’t replaceable but should last “the lifespan of the device” though Nest won’t specify what that is. None of our picks contain recycled content. Ecobee notes that it does not use conflict minerals or mercury, and also that it refurbishes and resells devices that have been returned and offers a three-year warranty on them; it also funds thermostat recycling programs so that mercury from traditional thermostats is safely reclaimed.
In terms of manufacturing and materials used, all of the companies note that the packaging they use is in part or completely recyclable, and some are even made from recycled or sustainable materials. For instance the packaging tray that the Honeywell Home T5 sits in is made from molded pulp, which is nearly 100% recycled content. Mysa says product packaging for its next model (though not the current one) will be 100% recyclable. Ecobee says almost all of its packaging and printed materials have been reduced, and are recyclable or compostable, and some are made from recycled materials. Ecobee’s company’s complete sustainability statement can be found here. Nest says 96% of its packaging is recyclable paper or fiber-based material.
None of these companies offer discounts or incentives for upgrading from an older model, though both Ecobee, Honeywell and Nest are widely available at discounted prices from utility companies through partner programs. And while all of the companies encourage owners to recycle their devices when they eventually die, only Nest will provide a free shipping label and box for you to send in any thermostat for reclamation and data destruction, which you can learn about here.
Although we strongly recommend our picks for most people, there are some scenarios in which they might be more than you need or not the right fit for your setup. Here are a few other smart thermostats that are worth considering.
The Honeywell Home T9 Smart Thermostat is the least expensive smart thermostat available that works with external room sensors, and its sensors are excellent. Able to detect motion, temperature, and humidity, they’re the most robust sensors available for a DIY thermostat. In our testing, the T9 combined with sensors made our home very comfortable. Unfortunately, the T9 system doesn’t have any of these sensors in the main unit itself, so if you want those features where the thermostat is, you have to stick a sensor next to it—not an elegant solution. But beyond the sensors, the T9 just isn’t that smart. You can use geofencing or a Schedule, but not both, and although the sensors detect occupancy, you can’t use them to set your thermostat to Away Mode. There’s also no HomeKit support as there is in the T5. However, the T9 is competitively priced considering it comes with one sensor, so it is a good option if you want the capabilities that sensors provide but don’t need (or want to pay for) the more advanced features of the Nest or Ecobee platform.
If you don’t need to use remote temperature sensors, the Google Nest Thermostat is a less expensive, simpler model that replaces our previous pick, the Google Nest Thermostat E (that version is now available only through professional installers). It has a tactile touch bar in lieu of the signature dial control, doesn’t work with remote sensors, and doesn’t “learn” your heating and cooling schedule like its sibling. However, the Home/Away feature powered by the Google Home app is very reliable. During a four-day vacation this summer, it ran for a total of three hours, saving us energy and money. The Nest does have the same HVAC monitoring feature as our pick, and in our testing it effectively alerted us (in the app, on the device, and via email) to a problem with our unit. It correctly identified what was wrong so that when we called a repair person, he was able to fix it without spending costly time troubleshooting the issue—essentially, it paid for itself with that one repair visit. And at $130 it’s a good budget option, especially if you are invested in the Google Nest ecosystem.
The Ecobee3 Lite Smart Thermostat is a budget model with all the same capabilities as our Ecobee pick, minus built-in Alexa and the inclusion of occupancy sensors—that is, neither a built-in sensor nor a remote sensor (though it is compatible with the remote units). Once you buy two sensors to bring it to the same level of usability as our Ecobee pick (which comes with one remote sensor and also has a built-in sensor), you end up paying nearly the same price. As such, we recommend the Ecobee3 Lite if you live in a small home or apartment and don’t need more sensors, require a HomeKit-compatible thermostat, or want to control your home’s climate via a combination of scheduling and geofencing.
Google has confirmed that the Nest Thermostat will work with Matter, an emerging new smart-home standard intended to make smart-home gadgets universally compatible. This should mean that you can control your Nest thermostat from any participating ecosystem’s app—including the Alexa app and the Apple HomeKit app. Google has not said whether the Nest Learning Thermostat will be compatible. Matter support should arrive in late 2022.
Sinopé’s Wi-Fi version of its line-level thermostat is, at $115, less expensive than our current pick from Mysa and doesn’t require a Zigbee hub (as the company’s previous models do). In early testing of this model, we have been impressed. Though Sinopé doesn’t offer advanced smart features like Mysa’s Intelligent Eco Mode, the geofencing and HomeKit integration work well. We will update this guide when our testing is complete.
We have been testing the $60 Amazon Smart Thermostat and so far it works pretty well. It doesn’t support remote smart sensors, nor does it have Alexa built-in, so for voice control we had to pair it with an Alexa device and set it up using the Alexa app. Unlike higher priced models it doesn’t have a glass or plastic touchscreen or control wheel, nor does it display the weather. But it does do a lot of the smart stuff like our top picks including geolocation, or using “hunches” to automatically create a schedule after learning your home’s daily routine—at a price not much higher than a decent programmable remote. We aren’t ready to dub it a pick yet as we haven’t finished testing it, but hope to have a verdict soon.
Google has announced Nest Renew Basic and Renew Premium, a two-tiered service for its Nest line of thermostats intended to incentivize owners to make sustainable and efficient energy choices. The Basic tier will be free when it launches (an invitation is required) and will enable a feature called Energy Shift, which automatically adjusts your thermostat to make use of times of day when energy is cheaper in your locale (where available). The Premium plan includes Clean Energy Match, a system that offsets your energy usage with credits Google has purchased from more than 50 renewable energy sources; access costs $10 a month.
Cync, previously known as C by GE, has released the $120 Cync Smart Thermostat. It can be installed without a common wire, and can be paired with the new Cync Room Temperature Sensors to monitor individual rooms. We plan to test it soon.
We tested all of the following models, and although they met most of our initial criteria and some even have lower prices than our picks, each suffered from flaws significant enough to prevent us from recommending them.
The Emerson Sensi Touch is an upgraded touchscreen version of the Sensi Wi-Fi (a previous budget pick in this guide). Although it offers geofencing as an option over a fiddly Schedule setup, you have to set heating and cooling separately, and there’s no option for customized geofencing or temperature setpoints for Home/Away/Sleep—instead, it simply sets your thermostat back 3 degrees when you exit a 3-mile radius.
The $80 Wyze Thermostat is the cheapest smart thermostat we’ve seen, and it employs geofencing and a built-in motion sensor to detect your presence and then switch the system mode to Home or Away. But in our testing, geolocation was unreliable—when our household was on vacation, it continued to run our system for seven to 10 hours a day. It also lacks a pre-cooling/heating feature, so it took a really long time to cool down our test home, and it was never at the scheduled temperature at the right time. On top of that, the learning features and remote sensors (to detect temperature, humidity, and motion) that Wyze has promised have yet to materialize. It works with most HVAC systems and does require a C wire but comes with an adapter kit.
The Honeywell Home Round (originally the Lyric) is appealing design-wise. But there’s no reason to buy this thermostat over its less expensive sibling, the T5, unless you have a complicated system (it’s compatible with more systems than the T5 is) or the space-age, circular, white design fits better with your home’s aesthetic.
Johnson Controls’s Glas smart thermostat is straight out of Star Trek, with a stunning 5-inch, OLED touchscreen that is very responsive (and quickly soiled by fingerprints). But its intelligence is strictly 21st century and based solely on its built-in occupancy sensor. Otherwise, it works just like a programmable thermostat you can control with Alexa or Google Assistant.
The Lux Kono has an unusual scheduling process that tells you how much your energy costs will increase or decrease based on the changes you make; it also offers changeable faceplates in multiple colors. Its click-wheel user interface is not intuitive (the company had to add reminder notes behind the faceplate), and multiple owner reviews report significant problems with temperature adjustments and inconsistent temperatures.
The basic-looking iDevices Thermostat has a tiny screen that’s glaringly bright, with no dimming. Its user interface is confusing, and the physical buttons don’t light up, so you can’t see them in the dark. It has geofencing but otherwise is just a programmable thermostat, and changing a Schedule once you’ve set it is tricky.
Energy Star Smart Thermostat Fact Sheet (PDF)
Hugh Langley, The best smart thermostats for your home, The Ambient, April 24, 2020
Megan Wollerton, The best smart thermostats of 2020, CNET, November 2, 2020
Jennifer Pattison Tuohy writes about smart-home technology use and sustainable living, while trying to practice both (one is a lot easier than the other).
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