Best Smart Thermostats for Heat Pumps UK 2026

Why Heat Pumps Need Different Thermostats

Your old gas boiler was simple. The thermostat said "heat on", the boiler fired up to 70°C, blasted hot water around your radiators, and switched off when the room hit temperature. On/off control worked fine because gas boilers are designed for short, aggressive burn cycles.

Heat pumps are fundamentally different. They work best running gently for hours, sometimes all day, at a low flow temperature (30–45°C). When a basic thermostat forces a heat pump to cycle on and off, it's like driving a car by flooring the accelerator then slamming the brakes. You'll get there, but you'll use twice the fuel.

The magic word is modulation. A thermostat that can tell the heat pump "run at 35°C flow temperature" is fundamentally different from one that just says "on" or "off". The protocol that enables this is called OpenTherm, an open communication standard that lets the thermostat and heat pump have a proper two-way conversation about what's needed.

Here's the catch: most UK heat pumps don't support OpenTherm natively. Vaillant uses its own eBUS protocol. Mitsubishi has MELCloud. Samsung has SmartThings. Only Daikin and a few others speak OpenTherm out of the box. So buying a fancy OpenTherm thermostat for a Vaillant Arotherm is a bit like buying a French phrasebook for a trip to Japan.

The other key concept is weather compensation, which adjusts the flow temperature based on the outdoor temperature. On a mild 12°C day, your heat pump barely needs to work. On a -3°C night, it ramps up. The good news? Most modern heat pumps (Vaillant, Mitsubishi, Daikin, Samsung) do this internally using their own outdoor temperature sensors. A third-party thermostat that overrides this with on/off control actually makes things worse.

Check Your Heat Pump First

Before spending £100+ on a thermostat, find out what your heat pump already does. Your existing controller might be handling weather compensation perfectly well. If so, you only need a smart thermostat for convenience features like app control and scheduling, not for efficiency.

Our Picks

Best Overall: tado° Smart Thermostat X

The tado° X is the latest generation and it earns the top spot for one reason: it's the most polished OpenTherm thermostat you can buy in the UK. When connected via OpenTherm, it can modulate your heat pump, telling it to run at 35°C flow temperature on a mild day and 45°C when it's genuinely cold, instead of just flicking it on and off like a light switch.

The geofencing is genuinely useful with a heat pump. It detects when the last person leaves the house and gently backs off the heating, then pre-warms before you get home. For a heat pump, "gently" is the key word; unlike a gas boiler, you can't crank a heat pump up for a quick blast of warmth. The tado° understands this and makes gradual adjustments rather than demanding a sudden spike in output.

The X model uses the new Matter protocol alongside its existing smart home integrations, so it works with Alexa, Google Home, and Apple HomeKit. The app is clean, the hardware looks good on the wall, and tado° makes matching Smart Radiator Thermostats if you want per-room control; more on that later.

The catch: tado° charges about £3/month for "auto-assist", which is the bit where geofencing and open window detection work automatically instead of needing manual confirmation. The core thermostat works fine without the subscription, but it's annoying. It's the kind of thing that should just be included at this price point. Still, if your heat pump supports OpenTherm, the efficiency gains from modulation more than cover £36/year.

The bigger catch: if your heat pump doesn't support OpenTherm (Vaillant, Samsung, Grant, most Mitsubishi models), the tado° X falls back to on/off relay control. At that point, it's just an expensive on/off switch with a nice app. Check compatibility before you buy.

Best Value System: Drayton Wiser

If tado° is the premium option, Drayton Wiser is the smart choice for people who'd rather spend less upfront and nothing ongoing. The starter kit with thermostat and two TRVs comes in around £120–£160, and crucially there are no subscription fees ever. Everything works from day one, no monthly ransom.

Newer Wiser models support OpenTherm, putting them on par with tado° for heat pump modulation. The app isn't quite as slick; it's functional rather than beautiful, but it does everything you need: scheduling, boost, holiday mode, energy reports. The real strength is the TRV ecosystem. Wiser TRVs are noticeably cheaper per valve than tado°'s (typically £35–45 vs £50–70), so kitting out a whole house costs significantly less.

Drayton is owned by Schneider Electric, which means solid UK installer support and a brand that's been in the heating game for decades. Your plumber has probably fitted a Drayton valve before. That matters when something needs troubleshooting.

The multi-zone control works well out of the box. Each room with a TRV becomes its own zone, so you can heat the living room to 21°C while keeping bedrooms at 17°C. With a heat pump, this kind of zoning is valuable; every degree you don't heat saves electricity.

Who should buy this: anyone who wants a solid smart heating system with good TRV support and doesn't want to pay tado° prices or subscription fees. If you're kitting out more than three rooms with TRVs, the savings on valves alone make Wiser the better deal.

Best for Heat Pump Optimisation: Homely Energy

Homely is the oddball in this lineup, and that's exactly why it's interesting. While every other thermostat on this list was designed for gas boilers and then adapted for heat pumps, Homely was built from the ground up specifically for heat pumps. It doesn't just communicate with your heat pump; it actively optimises how it runs.

Instead of relying on OpenTherm (which most UK heat pumps don't support anyway), Homely integrates directly with heat pump manufacturers. It reads the outdoor temperature, your home's thermal characteristics, your energy tariff, and weather forecasts, then automatically adjusts the flow temperature and scheduling to minimise running costs. They claim up to 31% reduction in running costs, and while that figure will vary depending on how badly your system was set up before, independent reports suggest 15–25% is realistic for most homes.

The installer dashboard is a genuinely clever touch. Your heating engineer can remotely monitor your system, spot issues, and adjust settings without a site visit. If your flow temperature is set too high or the system is cycling excessively, they'll know.

The catch: Homely requires an annual subscription (the exact price isn't publicly listed, which is never a good sign). Brand compatibility is growing but still limited; Mitsubishi Ecodan is the strongest integration, with Vaillant, Daikin, and others in various stages of development. It's also a relatively young company, so you're betting on them sticking around.

Who should buy this: anyone with a compatible heat pump who wants the system properly optimised but doesn't want to learn what weather compensation curves are. If you're the kind of person who wants to set it and forget it, Homely is the closest thing to a "just make it work properly" button.

Best Budget: Hive Mini

Let's be honest: not everyone needs or wants to spend £150+ on a thermostat. The Hive Mini does the basics well for £80–£120, and here's the thing: for many heat pump owners, the basics are all you need.

The Hive doesn't support OpenTherm. It's on/off relay control only. But here's why that's often absolutely fine: most modern heat pumps from Vaillant, Mitsubishi, Daikin, and Samsung have their own built-in weather compensation that adjusts flow temperature automatically using the outdoor sensor that came with the unit. If your heat pump is already doing the clever modulation stuff internally, you don't need the thermostat to do it too.

What the Hive gives you is smart scheduling, app control from your phone, and geolocation, so you're not heating an empty house. It's well supported by British Gas and other UK energy suppliers, the hardware is simple and reliable, and there are no subscription fees.

If your installer tells you the heat pump handles weather compensation on its own, save your money and go with Hive. Spend the £100 you saved on a couple of smart TRVs instead; you'll get a bigger efficiency gain from not heating empty rooms than from a fancier thermostat.

Best for Google Homes: Google Nest Learning Thermostat (3rd Gen)

If your house already runs on Google Home, the Nest 3rd Gen is the natural choice. The auto-learning schedule is its party trick; it watches your routine for a week, then builds a heating programme automatically. And the display is genuinely gorgeous. It's the only thermostat on this list that people actually compliment.

The hardware is beautiful and the software is polished. It's been on the market for years with a proven track record, and it integrates seamlessly with Google Home and Google Assistant for voice control.

The main limitation: it's relay-based (on/off) rather than OpenTherm, so it can't modulate a heat pump's flow temperature the way tado° or Wiser can. For a gas boiler this doesn't matter much, but for a heat pump it means slightly less efficient operation. If you've got a heat pump, tado° is the better choice for efficiency.

The other downside: there are no native Nest TRVs. If you want per-room control (and with a heat pump, you really should), you'll need third-party TRVs that may or may not play nicely with the Nest ecosystem. The tado° and Wiser systems have fully integrated TRV ranges. That's a significant practical advantage.

Who should buy this: people already deep in the Google Home ecosystem who want a gorgeous thermostat and don't need OpenTherm modulation. If you've got Google speakers in every room and use Google Home for everything, the Nest ties it all together nicely.

Best for Vaillant Owners: Vaillant sensoCOMFORT

This is the sleeper pick that most "best thermostat" articles ignore entirely, because it only works with one brand. But if you have a Vaillant heat pump (and Vaillant is the UK's most popular heat pump brand) the sensoCOMFORT is genuinely better than any third-party thermostat you can buy.

Here's why: Vaillant heat pumps don't use OpenTherm. They use their own proprietary protocol called eBUS, which allows much deeper two-way communication than OpenTherm can achieve. The sensoCOMFORT speaks eBUS natively, so it has full access to every parameter in the heat pump: flow temperature curves, compressor speed, defrost cycles, energy monitoring, fault diagnostics. A tado° or Nest connected to a Vaillant can only do on/off switching. The sensoCOMFORT can do everything.

Weather compensation is built in and works properly because the sensoCOMFORT and the heat pump were designed as a system. You can monitor energy consumption in the myVAILLANT app, adjust heating curves remotely, and your installer can diagnose problems without a site visit.

The sensoCOMFORT is often included with new Vaillant installations, or available as an add-on for £100–£150. The app isn't as polished as tado° or Nest; it's functional but a bit clunky, but the control it gives you over a Vaillant system is unmatched.

If you have a Vaillant Arotherm Plus, use the sensoCOMFORT. Don't waste money on a tado° that can only talk to your heat pump in on/off grunts when the sensoCOMFORT can have a full conversation.

Side-by-Side Comparison

The Real Question: Do You Even Need One?

Here's what nobody else in the thermostat review game will tell you: if you have a Vaillant, Mitsubishi, or Daikin heat pump installed by a competent MCS-certified installer, the manufacturer's own controller with properly configured weather compensation curves will probably run your system more efficiently than a tado° or Nest in on/off mode.

The only genuine reasons to add a third-party smart thermostat are:

• App control and smart scheduling: convenience, not efficiency. Being able to adjust heating from the sofa or set a schedule from your phone is nice.
• Geofencing: automatically reducing heating when everyone's out. This does save real money, typically 5–10%.
• OpenTherm modulation: but only if your heat pump actually supports it. If it doesn't, you're paying for a feature you can't use.
• Per-room control via smart TRVs: this is actually the biggest win, and you need a compatible hub thermostat to coordinate them.
• Your installer didn't optimise the weather compensation curves: this is depressingly common. Before buying a thermostat, ask your installer to review the heating curves. It's free and often makes a bigger difference than any smart thermostat.

If none of those apply to you, if your heat pump's built-in controller works fine and you don't need app control, save your money. Seriously. A properly configured manufacturer controller is better than an improperly configured smart thermostat, every single time.

Running Cost Savings

The savings from different thermostat types vary enormously depending on your heat pump, your house, and how well the system was set up in the first place. But here's a realistic breakdown based on a typical 3-bed semi with a heat pump running about £800–£1,200/year in electricity:

Notice something? A properly set manufacturer controller costs nothing extra and delivers comparable savings to an OpenTherm thermostat. The first thing to do isn't buy a new thermostat; it's make sure your existing one is set up correctly. Get your installer to check the weather compensation curves. It takes 15 minutes and it's the single biggest efficiency improvement most heat pump owners can make for free.

Homely's claimed 31% saving is the highest, but it depends heavily on how poorly your system was running before. If your installer already optimised things, you'll see less improvement. If your system was badly configured, Homely could genuinely transform your running costs.

Smart TRVs: The Real Efficiency Multiplier

Here's what will actually save you the most money on top of any thermostat: smart TRVs. Adding thermostatic radiator valves to individual rooms means you stop heating rooms nobody's in. If you're at work all day and only use the living room in the evening, why are three bedrooms being heated to 21°C?

With a heat pump, this matters even more than with a gas boiler, because every unnecessary degree costs electricity. Smart TRVs typically save an extra £50–£100 per year on top of whatever your thermostat saves. Both tado° and Drayton Wiser have excellent TRV ecosystems; if per-room control is important to you, these two are clearly ahead of the others.

Check out our full smart TRV comparison guide for a detailed breakdown of which TRVs work best with which thermostats.

Total System Cost: What You'll Actually Spend

A thermostat on its own is only part of the picture. Here's what a complete smart heating setup costs for a typical 3-bed house (thermostat + 4 TRVs + professional installation):

• tado° X system: £450–£550 (thermostat £150–200, 4 TRVs at £50–70 each, installation £50–80)
• Drayton Wiser system: £300–£400 (starter kit with 2 TRVs £120–160, 2 extra TRVs at £35–45 each, installation £50–80)
• Homely: £200–£250 upfront + annual subscription (no TRV support; takes a different approach to efficiency)
• Hive Mini + no TRVs: £80–£120 (the budget option; add TRVs later if you want)
• Nest 3rd Gen: £180–£220 (thermostat only; third-party TRVs are extra and may not integrate cleanly)
• Vaillant sensoCOMFORT: Often included with installation, or £100–£150 as add-on (no TRV ecosystem)

The Drayton Wiser system offers the best value when you factor in TRVs. The tado° system costs more but has a more polished app and wider smart home support. The Hive is the cheapest way to get smart control, and the sensoCOMFORT is essentially free if you've got a Vaillant.

For most 3-bed homes, the Wiser system pays for itself in two to three heating seasons through reduced energy waste. The tado° system takes slightly longer due to higher upfront cost, but the subscription fees mean it never fully "pays off" in the same way.

A Note on Installation

The Hive and Nest are DIY-friendly if you're comfortable with basic wiring; there are good YouTube videos for both. But if you want OpenTherm to work properly with a tado° or Wiser, it's worth asking your heat pump installer to set it up. Get the wiring wrong and the thermostat defaults to on/off relay mode, and you might not even realise you've lost the modulation that was the whole point of spending extra.

Homely requires professional installation and initial commissioning; they'll put you in touch with a compatible installer. The sensoCOMFORT should be set up by your Vaillant installer as part of the heat pump commissioning.

Five minutes of your installer's time to wire OpenTherm correctly is worth it. Don't let them rush this bit.

For more on cutting your heat pump bills, see our running costs guide. Still choosing a heat pump? Our best heat pumps guide covers the top brands. And use our heat pump savings calculator to estimate what you'll actually spend on running costs.