Smart Thermostat for a Heat Pump 2026: Guide and Best Models

For an air-to-water heat pump, the best smart thermostat in 2026 is one that talks to the heat pump rather than simply switching it on and off: the tado Heat Pump Optimizer X is currently the most complete solution for compatible brands (Daikin, Atlantic, Vaillant, Saunier Duval, Fujitsu, Panasonic). If your heat pump only accepts an on/off contact, a simple, well-set thermostat such as the Netatmo Thermostat Original is enough, and the Honeywell Home T6 remains a safe choice when the heat pump supports OpenTherm.

This guide is based on manufacturer specifications, independent reviews and verified buyer feedback. It only includes models currently sold in Europe. You will find the full selection in our smart thermostats catalogue.

Heat pumps and thermostats: what you need to know

A gas boiler copes well with frequent starts and stops. A heat pump much less so. Its efficiency (the COP) is best when it runs for long periods at reduced output, with the coolest possible heating water. Modern inverter heat pumps modulate their output and follow a weather compensation curve (heating curve): the milder it is outside, the lower the flow temperature.

The wrong thermostat can undermine this logic. If it switches the heat pump off and on again as soon as the room overshoots the set point by a few tenths of a degree, it causes short cycling: the compressor starts more often, wears faster and efficiency drops. The right thermostat for a heat pump either lets the unit modulate, or controls that modulation directly.

Three ways to connect a thermostat to a heat pump

• Volt-free (on/off) contact: the most common option. The thermostat opens or closes a contact on the heat pump’s room thermostat input. Simple and universal, but the heat pump only receives an on or off command.
• OpenTherm: a two-way communication protocol. The thermostat can request a higher or lower flow temperature depending on what the room needs. Not every heat pump supports it, so check the manual or the installed control module.
• Manufacturer-specific interface: some solutions plug into the heat pump brand’s own communication bus. This is how the tado Heat Pump Optimizer X works, giving it access to more settings than a simple contact.

How to choose

• Compatibility with your heat pump: the number one criterion. Note the brand and exact model of the indoor unit, then run them through the thermostat maker’s compatibility checker.
• Control type: on/off, OpenTherm or manufacturer interface. The richer the communication, the better the thermostat can preserve the heat pump’s modulation.
• Heat emitters: underfloor heating has high thermal inertia, so a thermostat that anticipates (learning, weather forecasts) is more useful than aggressive scheduling.
• Domestic hot water: if your heat pump also heats water, check that the thermostat or module can schedule it.
• Smart home ecosystem: Matter, Apple Home, Google Home, Amazon Alexa. Recent ranges use Matter, which makes integration easier.
• Subscriptions: some advanced features (dynamic tariffs, automations) are paid. Check what is included before you buy.

The best smart thermostats for heat pumps in 2026

1. tado Heat Pump Optimizer X: best choice for a compatible heat pump

The Heat Pump Optimizer X is not a classic room thermostat but a module that connects to the heat pump. It works with air-to-water, water-to-water and brine-to-water heat pumps from several major European brands: Daikin, Atlantic, Vaillant, Saunier Duval, Fujitsu and Panasonic, according to tado’s published list. It uses room temperatures measured by tado X thermostats and radiator thermostats to reduce the heat pump’s output, or put it on standby when rooms are warm, instead of switching it off abruptly.

Strengths: control of heating and hot water in the tado app, energy tracking, an installation guide tailored to the brand and model, a built-in Thread border router (no Bridge X needed) and Matter support. tado claims an average 22% efficiency gain; this is a manufacturer figure and should be read as a rough indication.

Limits: the list of compatible heat pumps is still limited, you need tado X thermostats or radiator thermostats for room-by-room control, and dynamic tariff features require the optional tado Balance subscription.

Best for: owners of a heat pump from a compatible brand who want the most advanced optimisation.

2. tado Smart Thermostat X: the versatile room thermostat

The Smart Thermostat X (wired version) replaces an existing room thermostat. It works over an on/off contact or OpenTherm, depending on what the heat pump accepts, and also suits water-based underfloor heating. It uses Thread and integrates with Apple Home, Google Home and Alexa through Matter.

Strengths: smart scheduling, geofencing, open window detection, a very complete app, and room-by-room expansion with Smart Radiator Thermostat X heads.

Limits: it needs a tado Bridge X or another Thread border router, and some automations are part of paid options.

Best for: heat pumps outside the Optimizer X list, or households that want a modern, expandable room thermostat.

3. Netatmo Thermostat Original: simplest and best value

Launched in early 2026, the Original range replaces Netatmo’s previous thermostat. It comes in a wired version (Thermo Hub included) and a wireless version (Thermo Link receiver and Thermo Hub included). Netatmo states it is compatible with most individual boilers and air-to-water heat pumps.

Strengths: guided installation, Auto-Adapt to anticipate heating based on the weather and insulation, Eco-Assist when you are away, monthly reports, Matter support via the Thermo Hub, and the Home + Control app.

Limits: the Original range is not compatible with older Netatmo accessories, so first-generation Netatmo radiator valves have to be replaced.

Best for: heat pumps controlled by a simple on/off contact and households that want a clean solution without complex setup.

4. Honeywell Home T6: the dependable OpenTherm option

The T6 (wired) and its T6R variant (wireless) are compatible with 24–230 V on/off and OpenTherm appliances, including heat pumps. They connect directly to Wi-Fi with no extra hub.

Strengths: clear touchscreen, geofencing, scheduling in the Honeywell Home (Resideo) app, and wide availability through installers.

Limits: the design and app feel less modern than tado or Netatmo, and room-by-room control is less integrated.

Best for: OpenTherm-compatible heat pumps and users who want a proven thermostat without being tied to an ecosystem.

What about the Google Nest Learning Thermostat?

Google has announced that it will no longer launch new Nest thermostats in Europe. The 4th-generation Nest Learning Thermostat is not sold there, and the 3rd-generation model is only available while stocks last. For a new purchase meant to last, the models above are a better bet.

What about the heat pump maker’s own controls?

Daikin, Vaillant, Atlantic and Panasonic offer their own thermostats and apps. They know the unit perfectly but often integrate less well with the rest of the smart home. They are worth considering, especially if your installer has already planned for them.

Comparison table

Mistakes to avoid

• Buying without checking compatibility: a heat pump without a thermostat input, or with locked controls, will not work with just any model.
• Scheduling deep night setbacks: with a heat pump, especially on underfloor heating, setbacks of 4–5 °C force the unit to work hard in the morning, often using the electric backup heater. Keep setbacks modest.
• Setting the switching differential too tight: it multiplies short cycles.
• Forgetting the weather compensation curve: a smart thermostat complements a well-set heating curve, it does not replace it. Ask your installer to fine-tune it.
• Putting the thermostat in the wrong place: near a window, a fireplace or in direct sun, it reads the wrong temperature.

Installation and safety

Always switch off the heat pump’s power supply before working on it. Replacing a wired thermostat on a volt-free contact or OpenTherm is within reach of a careful DIYer who follows the app’s guide. However, connecting a module to the heat pump’s control board, or any work on an installation under warranty, should be left to the installer or a qualified electrician: a wiring mistake can damage the electronics and affect the warranty.

Mount the thermostat in the main living room, on an interior wall, about 1.5 m above the floor, away from heat sources and draughts. Also check Wi-Fi or Thread coverage at that spot.

Grants and incentives

A smart thermostat bought on its own is rarely subsidised, but controls can be part of the quote for a heat pump installation that qualifies for public support schemes. Rules change regularly, so check official government sources or an energy adviser before signing a quote. To go further, read our smart home energy savings guide and our comparison of smart energy monitors, handy for tracking the heat pump’s real consumption.

Our verdict

If your heat pump is on the compatibility list, the tado Heat Pump Optimizer X is the most complete solution: it controls the heat pump itself, not just a contact. For an on/off heat pump, the Netatmo Thermostat Original offers the best balance of simplicity and features. The tado Smart Thermostat X and the Honeywell Home T6 are the right picks to make use of OpenTherm. Either way, have your heat pump’s weather compensation curve checked first: it drives most of the efficiency.