Which is the best smart thermostat?
Everything is smarter these days, but the thermostat market has really benefited from the intelligence 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 they can turn off the boiler earlier, saving money and keeping your home at the temperature you desire. Winters no longer have to be hideously expensive or uncomfortably chilly, as you can see from our best smart thermostats.
The most important thing is to buy the right smart heating system for you, which is why this list contains so much choice. Before we get started, let’s run through a few basics. There are two main types of system to choose from: standalone heating systems and systems with smart radiator valves. Individual thermostats simply replace your existing system, taking one single reading for your home. While you can still save money and increase usability, these smart systems have the same problems as dumb ones: some rooms can get too hot, others can get too cold. A part-way solution is to go with multiple heating zones, using two or more smart thermostats to control zone valves.
Smart radiator valves fit onto your thermostatic radiator valves (TRVs), 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. And some smart radiator valves can be used individually with a regular thermostat, letting you upgrade your home for comfort without having to touch your boiler: a trick that’s particularly useful for renters.
Smart thermostats can save you money, and 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, as not all models provide the necessary kit.
How we pick the best smart thermostats
The only way to accurately 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 to compare each model. For smart radiator valves, which control an individual radiator, we have a traditional hot water radiator in the same room to which we attach the valve, giving us a proper comparison between rival systems.
Usability is key when testing smart thermostats, so we test how easy it is to program schedules on each. Beyond that, we test the more advanced features for reliability. These include geolocation, which will automatically turn off your heating as you go out, and turn it back on as you return home.
It’s becoming increasingly important for smart thermostats to be able to talk to other devices and voice assistants. 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.
Although this adds to the initial set-up cost – you’ll need a £59 TRV per radiator – it should 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 temperature of your home at a glance. In addition, the Evohome has a dedicated touchscreen controller, 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 also been added, 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, as does Google Home support.
Honeywell’s Evohome is among the most expensive systems around, but it’s also one of the best – and ideal for larger installations.
Read our full Honeywell Evohome review
Heating type: Smart thermostats and underfloor heating, Boiler connection: OpenTherm, On/Off, Hot water control: Yes, Geofencing: No, Smart assistants: Amazon Alexa, Google Assistant
2. Nest Learning Thermostat
A powerful and intelligent single smart thermostat
As the name suggests, the thermostat learns how you like your home heated, and uses this information to create an automatic schedule for you. Unsurprisingly, there’s an initial learning curve – in the first few weeks, the Nest may not work quite the way you want it to. Over time, however, it should prove more effective than a manually set schedule on another thermostat.The thermostat uses presence detection to turn on and off automatically, depending on whether anyone is at home.
The Nest is brilliant at talking to other devices via the Works With Nest program, and a variety of other smart devices will interact 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 (though 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.
Read our full Nest Learning Thermostat review
Heating type: Single thermostat, Boiler connection: OpenTherm, On/Off, Hot water control: Yes, Geofencing: Yes, Smart assistants: Amazon Alexa, Google Assistant
3. Vestemi Radbot
Smart radiator valves that don’t need any programming
The Radbot looks like a standard TRV, and has a simple control dial that moves from 1 to 5 – these numbers correspond to a room temperature of between 15C and 24C. It would have been easier if Vestemi had put the temperatures on the dial, to be honest. But that’s our only criticism, as otherwise, Radbots are brilliant.
The system learns how you use a room by tracking how light changes during the day, such as when you open the curtains or turn the lights on and off. It turns the heating up when you’re in a room, and down when you’re not. And if you get cold, there’s a boost button on top. Even better, the Radbot works with your existing heating system, so there’s nothing to hook up to the boiler. If you want a smart solution that’s simple and cheap, this is the product for you.
Read our full Vestemi Radbot review
Heating type: Smart radiator valve, Boiler connection: None, Hot water control: No, Geofencing: No, Smart assistants: None
4. Nest Thermostat E
A very simple thermostat to install
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, and you can use the outer dial to adjust it. The excellent Nest app lets you take more control and adds in features such as geolocation, 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 to, and avoid overshooting the temperature you want.
If you’re looking for a simple smart upgrade to an existing dumb wired thermostat, this is a great choice.
Read our full Nest Thermostat E review
Heating type: Single thermostat, Boiler connection: On/Off, Hot water control: No, Geofencing: Yes, Smart assistants: Amazon Alexa, Google Assistant
5. Netatmo Smart Thermostat
Cheap to buy, with the upgrade option of smart radiator valves
The Netatmo Smart Thermostat is one of the cheapest systems of its kind that 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, you can expand it to fit your needs. You can adjust your main heating via the battery-powered E Ink thermostat, which looks gorgeous. And, as it’s portable, it’s easy to keep the room that you’re using at exactly the right temperature.
A simple smartphone app makes control straightforward both at home and away, with easy scheduling making it possible to keep your home at the right temperature hour by hour. Presence detection that switches your heating on and off automatically is not built in, but you can add this using IFTTT. The smart radiator valves also 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 major voice systems. While the thermostat lacks a little of the polish you’ll find in more expensive systems, its low price makes it an appealing prospect.
Read our full Netatmo Smart Thermostat review
Heating type: Single thermostat (optional smart radiator valves), Boiler connection: On/Off, Hot water control: No, Geofencing: No, Smart assistants: Amazon Alexa, Google Assistant, Apple HomeKit
6. Tado Smart Thermostat
A powerful and upgradable smart thermostat
Tado launched with the 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, so you can choose the home temperature that you want hour by hour. There are also options for when you’re out – choose from maximum savings (which may mean you return to a colder home) or maximum comfort (you’ll spend more to keep your home warmer). The app is simple to use, making the Tado Smart Thermostat one of the easiest systems to program.
Tado’s system is also very flexible. With the launch of its smart radiator thermostats, the system can be as powerful as Evohome’s. However, Tado’s radiator valves aren’t quite as smart, and the app’s zone handling isn’t quite as easy to use, as those of Honeywell.
The addition of Amazon Alexa and Google Home support, IFTTT and HomeKit (via the V3+ internet bridge) make Tado’s Smart Thermostat one of the most powerful available. The downside is that the new system requires a monthly subscription to enable automatically turning off the heating when you go out, plus the window detection feature, which turns off the heating when a door or window is open. Thinking of the subscription as ensuring the ongoing development of the app and system makes it easier to accept the cost. And you may decide you only need to pay for the extra features during the winter months, as you can cancel your subscription at any point.
Read our full Tado Smart Thermostat Review
Heating type: Single thermostat (optional smart radiator valves), Boiler connection: OpenTherm, On/Off, Hot water control: Yes, Geofencing: Yes (via subscription), Smart assistants: Google Home, Amazon Alexa, Apple HomeKit
7. Hive Active Heating 2
No longer just a heating system
The neat smartphone app makes it simple to set up schedules, and can track your location, so that your heating activates automatically depending on whether or not you’re at home. There’s also hot water support.
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 finessing is required (there’s no dedicated physical switch for the light bulbs, for example), but the add-ons are making Hive a more compelling choice as they build up. Amazon Alexa and Google Home support is now available.
If you’re happy with DIY, buying a thermostat you can fit yourself costs £179. Professional installation is included if you shell out £249.
Read our full Hive Active Heating 2 review
Heating type: Single thermostat (optional smart radiator valves), Boiler connection: On/Off, Hot water control: Yes, Geofencing: Yes, Smart assistants: Amazon Alexa, Google Assistant
These 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. Remote control via a smartphone app means you can turn your heating on or off wherever 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, your heating settings will 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 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 from 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 kit to have a built-in encryption chip.
Some thermostats also 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.
Best smart thermostats – What is ‘call for heat’?
This might seem like an odd riddle, but an increasing number of smart radiator valves can’t ‘call for heat’. Instead, they give you finer control over a room’s temperature than a traditional mechanical thermostat, which will just let you set your controls between one and five without giving you any indication what this means. Smart valves shut your radiators down when the desired temperature has been reached.
So, why would you want to choose this route? If you’ve got an old boiler that you can’t upgrade, or you’re a renter and can’t upgrade your smart heating, these options can be a nice addition. And if you’re looking for something to work with an existing smart thermostat to give a bit more control, such devices can be useful.
Be careful, though. If you have a smart radiator thermostat near your main thermostat, you may find that your main thermostat doesn’t ever hit the set temperature, so you could waste money pumping hot water around your system without it ever shutting off. Don’t just focus on the smart radiator valves that are sold individually, as some of the bigger companies let their products work independently. For example, Tado Smart Radiator Thermostats will work without the main heating controls, but give you the option to upgrade to a full call-for-heat system later.
Best smart thermostats – Can they really save me money?
In short, yes; smart thermostats can genuinely save you money on your smart heating. According to Tado, UK customers can save up to 19% on heating costs in comparison to the costs of using a traditional dumb thermostat and normal heating controls, as our full guide to how much money a smart thermostat can save you explains. Cost savings are achieved in multiple ways, and range from smart systems knowing when to shut down your heating earlier, to the fact that smart thermostats are a lot easier to program and control. Models with geofencing can help you make bigger savings by shutting down your heating automatically when you go out and turning it on when you return, so you only heat your home when you need it to be warm.
To get the maximum savings from your smart thermostat, it’s important to configure your model correctly. We’ve put together a guide showing you the settings and tweaks that you can use to maximise savings from your smart heating system. Ultimately, though, the best way to save money on heating is to turn down the dial on your thermostat. It’s estimated that each degree you turn down can save between 1% and 3% on your heating bills.
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