Underfloor heating thermostats explained: wired, wireless and smart

Thermostats are the part of an underfloor heating system you touch every day, so the choice affects comfort and running costs for years. This guide explains how UFH controls work, when you need wired or wireless, what a smart thermostat adds, how air and floor sensing differ, and which Heatmiser model fits which job. It ends with a priced example for a four zone ground floor.

How does an underfloor heating thermostat control the system?

A UFH thermostat is a switch: when the room is below the set temperature it sends a call for heat to the wiring centre, which opens the actuators for that room and switches on the pump and heat source. When the room is warm, the call stops and the actuators close.

1. The thermostat senses the room is cold and calls for heat.
2. The wiring centre powers that zone's thermal actuators on the manifold.
3. The actuators open the loops for that room, which takes a few minutes as they warm.
4. The wiring centre switches on the UFH pump and sends a demand signal to the boiler or heat pump.
5. Warm water flows through the loops until the thermostat is satisfied.
6. When no room is calling, the pump and heat source switch off.

That last step matters. The heat source and pump should only run when a room needs heat. This is known as boiler interlock, and a wiring centre handles it for you.

Do I need a thermostat in every room?

For new heating systems, and when the heat source is replaced in an existing home in England, the Building Regulations guidance says each room should have thermostatic room controls that separately adjust the heating in that room. With underfloor heating, that normally means one thermostat per room.

Approved Document L (2021 edition) allows a zone thermostat instead of room by room control in some cases, for example a single storey open plan home where the living area is more than 70% of the total floor area. New homes of 150m² or more should also have at least two independently controlled heating circuits.

Practical rules for a UFH layout:

• One thermostat per room or open plan space.
• One actuator per loop. A large room with three loops has one thermostat and three actuators.
• Rooms with very different uses, such as a bedroom and a living room, belong on separate zones even if they are small.

Check your own project with your building control body, because the 2021 guidance applies to work started under those rules and a new edition takes effect in 2027.

Wired or wireless: which UFH thermostat should I choose?

Choose wired thermostats when walls are open and you can run a cable to each room, and wireless when the rooms are finished and you don't want to chase walls. Both control the same actuators. The difference is how the signal reaches the wiring centre.

The Heatmiser Slimline-RF uses 868MHz radio with a range of up to 100m, and the Heatmiser neoAir runs on 4 AAA batteries. Mains powered neoStat thermostats also act as repeaters in the neo wireless network, which helps signal reach in larger homes.

There is also a 12V option. The neoStat 12V pairs with the Heatmiser UH8-N network wiring centre, which keeps mains voltage out of the thermostat back boxes.

What does a smart UFH thermostat add, and do I need a hub?

A smart thermostat lets you set times and temperatures from a phone app, and most Heatmiser smart thermostats need a neoHub plugged into your router to do that. Without the hub, a neoStat V3 still works as a normal programmable wall thermostat.

• neoHub G3: connects neo devices to the free neoApp, supports up to 32 devices, and works with Apple HomeKit, Google Home and Amazon Alexa.
• neoStat WiFi: joins your home WiFi directly, so no hub is needed. It suits a single zone or a small home. It does not work with the neoHub, so don't mix it with neoStat V3s on one app.
• Optimum start: neoStat, neoStat WiFi and Edge thermostats learn how long a room takes to warm up and start early to reach the set time. This is useful with underfloor heating, which heats slowly.

The Energy Saving Trust notes that smart controls can do everything conventional controls do, but whether they save money depends on how you control your heating now. Their value is mostly convenience: changing schedules or boosting a room without walking to the wall.

Air sensor or floor sensor: which do I need?

Most UFH rooms use the thermostat's built-in air sensor to control room temperature. Add a floor probe when you need to limit floor temperature, such as under wood or vinyl, or when the room temperature reading is unreliable, such as in a conservatory.

BS EN 1264 sets design limits for floor surface temperature: 29°C in occupied areas, 35°C in edge zones along outside walls, and 33°C in bathrooms. Many wood and laminate makers set a lower limit, so check your flooring instructions.

The neoStat V3 works with 10K, 12K and 15K NTC floor probes. The Edge and neoStat WiFi support floor sensing but the probe is sold separately. Lay the probe in conduit between two pipes so it can be replaced later.

Which Heatmiser thermostat suits which job?

Pick a dial for spare rooms and simple zones, a programmable wired thermostat for most new builds, and a wireless model for finished rooms. Prices include VAT, October 2026.

For electric underfloor heating, use a thermostat designed for electric floor heating, such as the Heatmiser neoStat-e (£83) or Slimline-E (£56). The water UFH thermostats above switch a wiring centre, not a heating cable. The neoStat V3, neoStat WiFi and Edge, for example, are rated at 3A maximum switching current.

What does a full UFH control system cost?

A wired smart system for four rooms costs about £600 in Heatmiser controls and actuators, and the wireless equivalent about £690. Here is a worked example for a ground floor with four rooms and six loops.

• Wired smart: 4 neoStat V3 (£308) + UH4 wiring centre (£64) + neoHub G3 (£162) + 6 actuators at £12 (£72) = £606.
• Wireless smart: 4 neoAir (£320) + UH8-RF wiring centre (£134) + neoHub G3 (£162) + 6 actuators (£72) = £688.
• Wired, no app: 4 Edge (£188) + UH4 (£64) + 6 actuators (£72) = £324.

If you plan more than four zones, or might add rooms later, use the UH8 8 zone wiring centre (£77) instead of the UH4. Wiring should be done by a qualified electrician.

What temperature should I set my underfloor heating thermostat to?

Set each room to the lowest temperature you find comfortable, which for most people is 18 to 21°C, according to the Energy Saving Trust. They estimate that turning a thermostat down from 22°C to 21°C could save about £120 a year in Great Britain.

Underfloor heating responds slowly, because it warms a heavy floor before it warms the room. Two habits help:

1. Use a small night setback of a few degrees rather than switching rooms off, so the floor doesn't have to recover from cold. Many installers set this as standard.
2. Turn on optimum start so the thermostat begins heating early enough to hit the set time, instead of you turning it up.

Turning the thermostat up higher does not heat the room faster. It only makes it overshoot.

Products for this job

• Heatmiser neoStat V3 smart thermostat 230V: £77
• Heatmiser neoAir wireless smart thermostat: £80
• Heatmiser UH8 8 zone wiring centre: £77
• Heatmiser neoHub G3: £162
• 2-wire thermal actuator 230V: £12
• All thermostats and controls

Related guides: Heatmiser neoStat vs neoAir vs Slimline, Floor probes, air sensing and floor limits and Zoning, thermostats and wiring centres.

Frequently asked questions

Can I use a normal room thermostat for underfloor heating?

Yes, a 230V room thermostat can control a UFH zone through a wiring centre. Choose one with optimum start and floor probe support if you have wood or vinyl floors, as UFH heats slowly and some finishes need a floor limit.

Do wireless UFH thermostats need a wiring centre?

Yes. Wireless thermostats like the neoAir and Slimline-RF send their signal to a wireless wiring centre such as the UH8-RF, which drives the actuators. For a single zone or a boiler, an RF-Switch receiver can be used instead.

Can one thermostat control two rooms?

It can, but each room will then heat to the same schedule and temperature. For new systems in England, the guidance expects room by room control except in limited cases such as large open plan single storey homes.

How long do neoAir batteries last?

Battery life depends on how often the thermostat is used and how it is set up. The neoAir runs on 4 AAA batteries and the Slimline-RF on 2 AAA batteries, so keep spares in the house.

Do I need a neoHub for Heatmiser thermostats?

Only for app control. A neoStat V3 or neoAir works as a normal thermostat without one. The neoStat WiFi connects to your router directly and does not use a neoHub.

What is the maximum floor temperature for underfloor heating?

BS EN 1264 design limits are 29°C in occupied areas, 33°C in bathrooms and 35°C in edge zones. Wood and some vinyl floors have lower limits set by the maker, which you enforce with a floor probe.

Can I control underfloor heating and radiators from the same app?

Yes, with a neoHub G3. The neoStat V3 works on both UFH and radiator zones, so every zone can sit on one neoApp. The neoStat-HW adds hot water timing to the same system.

Sources: Approved Document L, Volume 1 (gov.uk), Energy Saving Trust: heating controls, Danfoss UFH handbook (EN 1264 surface temperatures)