Best smart thermostat for a heat pump UK: which ones actually control one

Quick answer: Almost none of them. Hive states it cannot be fitted to a heat pump at all, and tado° sells a separate £219.99 Heat Pump Optimizer X that works alongside the heat pump’s own controller instead of replacing it. For most UK heat pump owners the right answer is to leave the manufacturer’s weather compensation in charge and add a third-party controller only for tariff shifting.

We haven’t tested these controls. This is based on manufacturer product pages, published compatibility lists and current UK prices, checked on 27 July 2026.

Why a normal smart thermostat is the wrong tool

A gas boiler is happiest producing a lot of heat quickly and then stopping. A heat pump is the opposite. It gets more efficient the lower the water temperature it has to produce, and it does its best work running gently for hours rather than blasting and stopping.

That’s the whole conflict. A conventional smart thermostat is a room-temperature switch: room cold, call for heat, room warm, stop. Apply that logic to a heat pump and you get short cycles at a high flow temperature, which is the least efficient way to run one. Weather compensation does the opposite. It reads the outside temperature and continuously trims the flow temperature, so on a mild day the heat pump might run all afternoon at 32C instead of stopping and starting at 45C.

Control sits alongside radiator sizing and your electricity tariff as one of the three things that decide what a heat pump costs to run. The Energy Saving Trust’s heat pump guide is the plain-English version. It isn’t a footnote.

What each system actually offers

tado° Heat Pump Optimizer X

This is the most credible mainstream option, and the design tells you why. At £219.99 it doesn’t replace your heat pump’s controller. It works alongside it, and tado° lists it as compatible with air-to-water, water-to-water and geothermal heat pumps, whether or not they’re already connected to a thermostat. The warranty is two years. Check your specific model on tado°’s compatibility tool before ordering, because air-to-water is a category, not a guarantee.

The reason to buy it is the Balance subscription, which shifts heat pump run time into cheap tariff windows. tado° charges for Balance separately from the hardware, so price it before you commit. On a time-of-use tariff with a big overnight price gap, that arithmetic can work. But on a flat tariff at the Ofgem cap rate of 26.32p/kWh there’s nothing to shift into, and the case falls apart.

More on the range in our tado° review.

Homely

Homely is a UK-marketed third-party heat pump controller, fitted by a registered Homely installer and quoted at under 45 minutes to fit. It lists compatibility with Midea, Ideal Heating, Samsung, Mitsubishi, Daikin, Worcester and Riello, and says it works with all tariffs, naming E.ON, EDF, Octopus Energy and British Gas among them.

There’s no price anywhere on the website, which we checked on 27 July 2026. So budget for a quote, not a shelf price. The site makes energy and carbon savings claims, and we found no published methodology behind them on the date we looked. That isn’t unusual in this market. It does mean treating the numbers as marketing until someone independent measures them. The tariff-shifting logic is sound in principle. How big the gain gets depends entirely on your tariff spread.

What we’d do

• New heat pump install: specify weather compensation and a properly sized emitter circuit, then use the manufacturer’s own control. That single decision matters more than any app.
• Flat-rate electricity tariff: don’t buy a third-party controller. There’s no price spread to exploit and you may make the heat pump run worse.
• Time-of-use tariff with a real overnight gap and a hot water cylinder to charge: a tado° Optimizer X at £219.99 plus Balance, or a Homely quote, is worth pricing.
• Existing radiators that are too small: fix that first. No controller compensates for an undersized emitter, because the heat pump has to raise flow temperature to get the heat in.
• Don’t zone a heat pump with smart radiator valves by default. Closing off radiators shrinks the emitter area and pushes flow temperature up. Reasoning in smart TRVs compared.

Grants and costs, so the control spend is in proportion

The Boiler Upgrade Scheme in England and Wales pays £7,500 towards an air source or ground source heat pump. There’s no income test and the scheme runs to March 2030. A targeted uplift to £9,000 applies only for homes currently heated by oil or LPG with no mains gas connection, and runs from 21 July 2026 to 31 March 2027. Air-to-air gets £2,500. VAT on heat pumps stays at 0 per cent until 31 March 2027. Details at gov.uk.

Our modelled estimate for a UK air source heat pump installation is £11,014 before grant, with a range from roughly £7,159 to £17,072 depending on property and region. Method at how we calculate costs. Against an £11,000 job, a £220 controller is small. Against getting the emitter sizing wrong, it’s irrelevant.

Background reading: our heat pump guide, the deeper dive at smart thermostats and heat pumps, and the wider control ranking in best smart thermostats UK 2026. If a battery or solar is also on the list, the tariff maths changes again.

FAQs

Can I use a Hive or Nest thermostat with a heat pump?

No. Hive states on its own product page that its engineers can’t install a Hive Thermostat on a heat pump, because testing isn’t complete. Google doesn’t market the Nest thermostats as UK heat pump controls either, and has said it will launch no new Nest thermostats in Europe.

Is weather compensation better than a smart thermostat?

For a heat pump, yes, as the primary control. Weather compensation continuously trims the water temperature to the outside conditions, so the heat pump runs gently at a low flow temperature. A room thermostat only switches the whole thing on and off. That’s the least efficient way to run one.

What does a heat pump smart control cost in the UK?

tado°’s Heat Pump Optimizer X is £219.99, plus whatever tado° charges for the optional Balance subscription (checked 27 July 2026). Homely doesn’t publish a price and is fitted through registered installers, so you’ll need a quote. Manufacturer controls from Vaillant, Daikin and Mitsubishi normally come with the heat pump.