The best smart thermostats you can buy

The first mass-market smart thermostat was launched way back in 2011, and in that time, Google estimates it has saved over 39 billion kWh of energy worldwide. It makes heating fashionable, while also giving homeowners greater control of the energy they use.

Available in stainless steel, white, black, and copper, it’s a stylish smart home gadget that works as well as it looks, with the tactile metal outer ring and colour display oozing class. It’s suitable for all boilers, and can manage hot water too, offers smartphone and voice control and – here’s the clever bit – it learns your routine, switching the heating on and off as you leave and return to the house, even when you go to bed. It understands the rhythm of your home and creates a heating schedule automatically.

This artificial intelligence (AI) is clever, using GPS to determine the household’s location, but suits people who would rather not think about heating schedules. It works, but if you are happy to set your own schedule, we think the same, or greater energy savings can be achieved. Thankfully, you can do it all manually via the app.

On test, we found it was quick to adjust either from the thermostat or using the app, both when connected to home wifi or 4G. And if you don’t want the thermostat fixed to the wall, you can buy a stand for £30. The app design is slick, giving loads of useful information, with features and data easily accessible.

After more than a month’s use, the self-learning feature adjusted our boiler’s schedule based on the time it took our home to heat up (we found we were heating our home for longer than needed). Buy more than one Nest - or the cheaper Nest Thermostat E for £119 - and you can create heating zones, although we think smart radiator valves, available with some models, are a better solution for total control.

Wiser by heating brand Drayton is a simple-to-install, no-frills smart thermostat system, that does all the basics brilliantly and has a few extra smart home tricks up its sleeve. At its most basic, the system works like the Hive setup, although without built-in geolocation features. You get a smart thermostat, control app and wireless hub for managing your home’s heating. There’s voice control too, and impressive energy-saving claims, but it’s when used as a multi-zone system that this kit shines.

It can control up to 32 radiator valves across 16 rooms, which should be enough for all but the biggest of mansions. The smart radiator valves, £44.99 each or £114 for three, are slim and discrete, and while they lack the temperature display that the Evohome ones have, if you twist the top towards the plus or minus symbols it will increase or decrease the radiator temperature by 2C for an hour. Basic but effective.

The smartphone app is also plainly designed and straightforward to use. Tap on your room of choice and you can adjust the schedule or current temperature for 30 minutes, one hour, two hours or three hours. On test, it wasn’t quite as fast as the Nest Learning thermostat at switching the heating on or off but it is self-learning and amended our schedule to cut energy waste. We also like the open-window detection feature that switches the heating off if it detects a draught and there’s a geofence that turns the heating on or off based on your phone’s location.

If you also have a home electricity meter, Wiser’s Insights+ dashboard (£14.99) can sync it with the smartphone app, bringing your electricity and heating data together in one place, with useful observations into where savings can be made. And speaking of electricity, Wiser can also control underfloor heating systems and has a smart plug socket (which costs £42) that can be managed via the same app, great for portable heaters, electric fires or just about any appliance.

The original Hive Thermostat remains a great choice but the latest model, the Thermostat Mini, is smaller, slimmer, arguably prettier, and considerably cheaper while having almost as many features.

The Thermostat Mini relies on your smartphone more than the original as it has fewer controls available on the thermostat. But the main features are there, including superb scheduling, holiday modes and heating boosts for when the weather turns chilly. Voice control is also comprehensive, available via Alexa, Google Assistant and Siri through Apple HomeKit. Once you’re installed, just ask.

It lacks the AI learning skills of our Nest top pick, but the Hive Thermostat Mini has geolocation services that can detect if you’ve left the house with the heating on, and it’s compatible with Hive’s security door sensors, which can trigger the thermostat to turn off. The system also has built-in Frost Protection, so if the temperature drops below 7C, it turns on the heating to warm your pipes.

Instead of a rechargeable battery or mains power, the Thermostat Mini requires four AAA batteries (included). The separate receiver is simple to install if you’re confident though, which helps keep costs down.

The Thermostat Mini should also appeal to people who already have the original but are looking to create an affordable multi-zone heating system. The Thermostat Mini costs just £59 if you don’t need the receiver and will slip effortlessly into your home – upstairs, for instance – enhancing the system’s overall efficiency. And if you need more control, Hive also has a smart radiator valve for just £59 each, which can create up to six different zones.

Hive’s Heating Plus subscription service is an extra £3.99 per month. It offers scheduling tips designed to save energy and has a carbon calculator for more in-depth energy analysis. Members get 10% off other Hive products too, although the subscription service isn’t yet compatible with the smart valves.

After a smart thermostat that looks stylish while also controlling your heating? We think this is the one to pick. Netatmo turned to renowned French designer Philippe Starck to create a minimalist package that delivers the information you need without drawing attention to itself. It’s a discreet white box that you can match with five different plastic surrounds to personalise the colour.

It has an easy-to-read e-ink display (the same type you’ll find on our favourite ebook readers) that shows the current temperature and the target, and you control it by tapping on the top or bottom of the box to raise and lower the temperature. The rest of the control (like changing schedule times and checking energy use) happens through the app – there are no other buttons on the unit.

On test, it proved quick at turning the heating on or off when we adjusted the temperature and we found the auto-adapt function useful as it tweaked our schedule based on how long our home took to heat up. There are expansion options here too, as you can turn it into a multi-zone system by adding Netatmo’s smart valves to each radiator in your home.

We like how this thermostat gives you multiple options for where to place it too, as you could set it on a flat surface without needing a stand, or mount it on the wall instead. If you’d rather have a colour display you’ll be a bit disappointed, and this thermostat lacks sensors that detect open windows and motion. It won’t work if you have a separate hot water tank either.

However, if you just need the basics this is an ideal option, and we think that the away mode (which turns the heating off for a set period of time) and the frost guard (which prevents the heating system from freezing) settings are useful too.

German brand Tado is now onto its third-generation smart thermostat, and it remains a solid performing alternative to Nest and Hive. It is an easy-to-install system with optional multi-zone heating and advanced GPS location tracking, which allows the thermostat to learn your schedule and adjust the heating accordingly.

It is clever enough to read the weather reports in the morning too, and it will tweak the heating schedule to keep you comfortable. It can tell when you have left a window open and will turn off the heating to save wasting energy. You can connect up to 25 devices to the bridge, including smart radiator valves, air conditioning control and temperature sensors.

But it is location tracking and multi-zone heating support where Tado shines. It has the ability to track everyone in the house (who has a smartphone) and adjust the temperature as you leave or arrive home. Unlike Nest, you can control each radiator in your home if you invest in the Tado smart radiator valves.

When we tried the system, we were impressed by the self-learning and how it effectively amended our schedule. Our tests proved it was quick to switch our heating on and off, and we like how it creates an energy report showing when the heating was on and what triggered it, as well as how much you spent on heating.

Controls on the thermostat are minimal so you’ll need your smartphone for detailed scheduling, and we also resent having to subscribe to Auto-Assist at £2.99 a month to get the best from the GPS services (as they used to be free on previous models).

The location services still work in free mode but you must physically control the heating, rather than the system doing it for you. The subscription does include Care & Protect, which monitors your heating remotely and can identify possible boiler problems, alerting you before disaster strikes.

While a few years old now, the Honeywell Lyric T6R or T6 are still solid options if you’re after convenience and value. More affordable than Honeywell’s expansive Evohome system, this is a basic alternative that delivers impressive features for the cost – the T6 is a replacement for a wired thermostat, while the T6R works wirelessly and costs a little more. Just note that you’ll need to make sure you’ve got a spare plug socket in a location near your boiler for the installation of the relay box.

It’s affordable for a self-learning thermostat, and we like how it automatically adjusts when the heating comes on to achieve the desired temperature at the time that you’ve put in the schedule. It doesn’t come with multi-zone capabilities or hot water control but we found that it does a great job of quickly switching the central heating on or off, even when you’re not at home. On test, we were impressed at how it noticed that we were heating the house for too long and automatically adjusted the heating schedule.

The thermostat and the app give you identical functions, so whether you want to turn the heating up or down, or adjust the schedule, you can use either your smartphone or the thermostat itself. We appreciate how it has a geofence function too, so it knows when the last person has left and it'll switch the heating off. We also love that the thermostat’s touch screen has a lock to prevent children from accidentally (or deliberately!) adjusting its temperature. There’s also a disable screen function that means you can easily clean the screen without messing up any of the settings. It works with Amazon Alexa, Google Assistant and Apple’s Siri too.

Because it’s a little older, though, it lacks some of the more advanced sensors found in other smart thermostats, though. There’s no colour screen and sensors such as humidity, open window and motion are missing.

The Nest Thermostat E is much simpler to install than our Nest thermostat top pick. The smart module, known as a Heat Link E, isn’t wired into your boiler. Instead, it replaces your existing wall-mounted or wireless room thermostat. This module then communicates with your boiler, so you don’t need a professional installer to connect a Heat Link to your boiler itself.

The thermostat is self-learning, so it automatically adjusts when the heating comes on based on how long it takes for your home to reach the desired temperature. It's not compatible with boilers that have a separate hot water system, but we still think it’s a flexible option that is great value for money.

During testing, it was just as fast as our top thermostat at adjusting the temperature of our home, and we like how it’s got the same smart features as the Nest Learning, too. This model lacks the stylish metal and glass design of the other Nest thermostat on our list, along with that model’s humidity, light and motion sensors. Instead, it has an all-white plastic design that may not look quite as appealing, but blends into any room decor.

It’s also worth noting that the Thermostat E doesn’t have a touchscreen like the other Nest model, instead using a ring around the thermostat to control it. We like how it comes with a built-in stand, making it easy to place in whichever room you like, and that it tells you how long it’s going to take to reach the intended temperature.

The Evohome is a premium-priced zoned heating system that, rather than heating your home in one go like the rest, has been designed to work with smart thermostatic radiator valves. You can set each room, or individual radiator, to heat up or switch off on demand. Compared to others on our list, this can get rather expensive. While it costs more to buy the hardware upfront, the added control and potential energy savings mean that it could pay for itself in just a few years.

The system is based around a large, now quite dated-looking touchscreen display, smartphone app, radiator valves and receiver, that connects wirelessly to the boiler. The display shows the temperature and status in each room, rather than the house. The detailed heating planner is simple to use too, both on the display and smartphone app, and it allows you to heat rooms at specific times.

The smart radiator valves are available with or without a temperature display from £59 each, but multipacks are available. They can be used just like a standard radiator valve, and a quick spin of the dial can adjust the temperature without reaching for your phone. There’s also support available for underfloor heating.

Being a multi-room system, control and set-up are a little more complicated than Nest or Hive, and there’s no AI learning, so it’s up to you to decide which temperatures are comfortable. But there is weather compensation, where the system adjusts the set temperature based on the weather forecast, and it can also shut down individual room heating when it senses a window is left open.

There’s also an away mode, which shuts everything down (but monitors temperatures) while you’re on holiday, and an eco mode which drops your normal temperature selections by a few degrees to maximise energy savings. When we tested this system, we were able to quickly see the temperature of every zone in the house, as well as the hot water temperature, and we found it was quick to switch the heating on or off.