Everything is smarter these days, but the thermostat market has really benefited from the upgrade. Being able to program your thermostat to turn or off at specific times and locations can save you a lot of cash. Even better, many smart thermostats learn how your home heats up, so can turn off the boiler earlier, saving money and keeping your home at a better temperature. Winters no longer have to be hideously expensive.
Out of the range of smart thermostats that we’ve tested, two stand out in particular. The Honeywell Evohome is the ultimate choice, giving you room-by-room control thanks to its radiator valves. If you’re on a tight budget, the Netatmo Smart Thermostat is an excellent choice, and it can be expanded with its own radiator valves at a later date.
Before we dive into the main reviews, it’s worth explaining a little about the two main choices for smart thermostats: individual and smart radiator valves. Individual thermostats simply replace the system that you have now, taking one single reading for your home. While you can still save money and increase usability, these systems have the same problems as dumb ones: some rooms can get too hot; others too cold. If you have multiple heating zones, you can often control them by buying multiple thermostats.
Smart radiator valves fit onto your radiator’s TRV, giving you room-by-room control of your heating. The upside is that you get schedules and individual heat control for each room, so you can save money by only heating the rooms that you use. The downside is that these systems are more expensive to install and control, and each radiator valve has batteries that need to be replaced. Some individual smart thermostats sell radiator valves as an optional add-on, letting you expand the system as your needs grow.
Smart thermostats can save you money, but to get the biggest savings, you should wire a compatible thermostat into the digital interface on your boiler. In the UK, this interface is primarily OpenTherm. Using OpenTherm, your smart thermostat controls the boiler’s heating temperature to pick the most efficient setting.
Related: What is OpenTherm?
Finally, if you have underfloor heating, find out if your smart thermostat can control this.
How we pick the best smart thermostats
The only way to truly compare smart thermostats is to have one person review them under the same conditions, something that Trusted Reviews is capable of. We wire all of our smart thermostats into an electric radiator, testing performance over a period of weeks in a single room. That lets us see how each thermostat performs and how it learns to adjust its settings to suit the room, giving us an accurate way of comparing each model. For smart radiator valves, which control an individual radiator, we have a traditional hot water radiator in the same room, which we attach the valve to, giving us a proper comparison between rival systems.
Usability is key when testing smart thermostats, so we test how easy it is to programme schedules on each. Beyond that, we test the more advanced features for reliability, such as geolocation, which will automatically turn off your heating as you go out, and turn it back on as you return home.
Increasingly, the ability for smart thermostats to talk to other devices and voice assistants is becoming more important. Our testing environment includes Amazon Echo and Google Home smart speakers, and an iPad for Apple HomeKit compatibility. We also test the IFTTT integration, if available, and how the system interacts with other smart home devices, such as through Samsung SmartThings.
1. Honeywell Evohome
The most powerful multi-room heating system.
No company has as much experience in the heating arena as Honeywell. It should be no surprise, then, that the company’s first smart product is so comprehensive. Rather than replacing your basic smart thermostat, the Honeywell Evohome adds room-by-room control through smart thermostatic radiator valves (TRVs).
Although this adds to the initial setup cost – you’ll need a £59 TRV per radiator – it will be possible to save money thereafter since you’ll only need to heat the rooms you’re using. Also, each room is set to its perfect temperature, making for a much more comfortable home environment.
Honeywell has refined and expanded its system since launch. The smartphone app has improved immeasurably, making it easy to control each room and view the state of your home at-a-glance. In addition, the Evohome has a dedicated touchscreen controller for your home, so you don’t need to reach for your smartphone. There’s now an OpenTherm boiler connector, too, if you want to save more money.
IFTTT support has been added, too, so you can control Evohome via other smart devices. For example, you can set your heating to turn off when you go out using IFTTT, making up for the fact that there’s no integrated presence detection. Amazon Alexa support lets you control the system with your voice, too, as does Google Home support.
Honeywell’s Evohome may be one of the most expensive systems around, but it’s also one of the best – and ideal for larger installations.
2. Netatmo Smart Thermostat
The Netatmo Smart Thermostat is one of the cheapest such systems you can buy, but that doesn’t mean it lacks features. In fact, it’s one of the most flexible heating systems around, and with the launch of smart radiator valves, it’s one you can expand to fit your needs. You can adjust your main heating via the battery-powered E Ink thermostat, which looks gorgeous. Since you can carry it around, it’s possible to keep the room you’re currently using at exactly the right temperature.
A simple smartphone app makes control while at home and away straightforward, with easy scheduling making it possible to keep your home at the right temperature hour-by-hour. There’s no built-in presence detection to switch your heating on and off automatically, but you can add this using IFTTT. More recently, the Smart Radiator Valves let you add room-by-room control, although the integration’s not quite as neat as Evohome’s.
Amazon Alexa, Google Home and Apple HomeKit integration make the Netatmo Smart Thermostat one of the few that can be controlled via the two biggest voice systems. While the thermostat lacks a little polish of more expensive systems have, its low price makes it an enticing prospect.
3. Nest Learning Thermostat
Think of smart thermostats and the Nest Learning Thermostat is likely to be one of the first to spring to mind. That’s for good reason, too, since this is the product that showed how powerful smart heating could be. Now in its third generation, the Nest Learning Thermostat remains one of the best smart thermostats you can buy.
As the name suggests, the thermostat learns how you like your home heated, thereafter creating an automatic schedule for you. Not surprisingly, there’s a bit of a learning curve. In the first few weeks, the Nest may not work quite the way you want it. Over time, however, it should prove to be better than a manually set schedule on another thermostat.
Presence detection lets the thermostat turn on and off automatically, based on whether or not you’re home . The Nest is also brilliant at talking to other devices. Via the Works With Nest program, a variety of other smart devices will work with your smart thermostat. For example, your Philips Hue lights can turn off when you go out. With an excellent IFTTT channel and support for Amazon Alexa and Google Home (HomeKit support doesn’t seem likely), the Nest is one of the best-connected smart thermostats available.
This latest version supports dual-zone plumbing and can be extended to support hot water systems, too. There are no smart radiator valves to add full zoning, however.
4. Nest Thermostat E
A very simple thermostat to install.
Forget expensive installations and hassle, the Nest Thermostat E has been designed so that it’s easy to install by practically anyone. The new Heat Link E battery-powered bridge just attaches to the wires your old wired thermostat used to use, and that’s it. Starting from scratch, most people should be able to get the system up and running in the less than an hour.
If you don’t have a wired thermostat, you’ll need to have the Heat Link E wired into your boiler, which will most likely mean a professional installation. While the system supports OpenTherm for increased energy savings, at this point you’re probably best with a different product. Nest has pre-programmed the Thermostat E with a schedule based on real data from existing Nest users. As you use the thermostat, it learns and updates your schedule.
The main thermostat has a diffused screen, helping it blend into the background. The screen shows you the temperature, but you can use the outer-dial to adjust temperature. The excellent Nest app lets you take more control and adds in features, such as geo-location, turning off your heating when you go out. True Radiant learns how your house warms up, so you can have it warm when you need and avoid overshooting temperature.
If you’re looking for a simple smart upgrade to an existing dumb wired thermostat, this is a great choice.
5. Tado Smart Thermostat
A powerful and upgradeable smart thermostat
Tado launched with the sole goal of making smart heating systems easy to use, and it certainly succeeded. The Tado Smart Thermostat is designed to track your location so that your heating goes off when you’re out and turns back on when you’re on the way home. It works brilliantly, and has the most reliable presence detection we’ve tested.
Since launch, Tado has updated the apps and web interface to add a new heating scheduler, letting you choose the temperature that you want your home at hour-by-hour. Plus, there are option for when you’re out, picking between maximum savings (with the potential to return to a colder home) or maximum comfort (spending more to keep your home warmer). The app is simple to use, making the Tado Smart Thermostat one of the easiest systems to programme.
Tado’s system is also very flexible. With the launch of the Smart Radiator Thermostats, the system can be as powerful as Evohome. However, Tado’s radiator valves aren’t quite as smart, and the app’s zone handling isn’t quite as easy to use as that of Honeywell.
Throw in Amazon Alexa and Google Home support, IFTTT and HomeKit (via the V3 internet bridge), and Tado’s Smart Thermostat is one of the most powerful available. If you don’t want to buy outright, you can even rent the kit, paying monthly for it.
6. Hive Active Heating 2
Not just a heating system anymore.
The original Hive system was rather basic, but all of the stops have been pulled out for the Active Heating 2. The freshly designed thermostat looks fantastic, giving the Nest a run for its money. It’s easier to use, too.
The neat smartphone app makes it simply to set up schedules, and it’s capable of tracking your location, so that your heating activates automatically depending on whether or not you’re at home. There’s hot water support, too.
A recent update adds IFTTT support, so you can finally integrate the Hive with other smart devices. Plus, Hive has a growing infrastructure of its own devices to help you build your own smart home, ranging from motion sensors to the new Hive Active Light smart lightbulbs. A little finesse is required (there’s no dedicated physical switch for the light bulbs, for example), but the add-ons are starting to make Hive a more compelling choice. Amazon Alexa and Google Home support is now available.
If you’re a happy DIYer, you can buy the thermostat for £179 and fit it yourself. Alternatively, you can buy it for £249, which includes professional installation.
Those are our top picks of the best smart thermostats. If you want to know more about how smart thermostats work and what to look out for when buying one, read on.
Best smart thermostats – What are the benefits?
Thanks to more advanced scheduling and the ability to learn how your home heats up, smart thermostats are more efficient than regular models and can save you a fortune in heating bills. Plus, by offering remote control via a smartphone app, you can turn your heating on or off, no matter where you are – which is great if you’re heading off on holiday and suddenly realise that your heating is still on at full power.
Best smart thermostats – What type do I need?
There are numerous smart thermostats to choose from, each offering a variety of features, so it’s important to pick the one that suits your lifestyle and home.
First, you need to consider the type of heating system you want. A regular smart thermostat, such as the 3rd-gen Nest Learning Thermostat, simply replaces your existing thermostat. Although you’ll still save money with such a system, it will be your heating settings that control your entire home.
With a zoned heating system, such as the Honeywell Evohome, you get room-by-room control via smart thermostatic radiator valves (TRVs). Such a system will save you even more money since you’ll be heating only the areas you’re using at any given time. The downside is that the initial outlay for such systems can be costly: typically around £50 to £70 per radiator. They’re a better option for houses with a greater number of rooms to control.
Best smart thermostats – What control options are there?
All smart thermostats should be controllable, to a degree, from the main unit as well as a dedicated smartphone app. Voice control is becoming a more important feature, in the form of Alexa on the Amazon Echo or Siri using Apple HomeKit. Being able to simply tell your thermostat to turn the heating up or down is a convenient way to control the temperature in your home. Alexa support is more widespread, with HomeKit support lagging since Apple requires that kit has a built-in encryption chip.
In addition, there are thermostats that offer presence detection via a smartphone. The models that do this well – the Tado, for example – can automatically turn off the heat when everyone is out, and turn it back on when the first person returns home. Again, this can lead to huge cost savings, as you’ll no longer be paying for heating that nobody is around to enjoy.
IFTTT support allows you to integrate other devices with your smart heating system. For example, you can use Tado’s presence detection to enable a smart camera to turn on automatically; or you can make your heating turn off automatically when the temperature outside hits a certain point. The combinations are almost limitless.
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