Underfloor heating vs radiators: cost to install and run (2026)

Quick answer: Wet underfloor heating costs about the same to run as radiators on a gas boiler turned down to 55°C, and roughly £56–£138 a year less on a heat pump, for a home needing 8,000kWh of heat at the October–December 2026 price cap. Electric underfloor heating costs 26.32p per kWh of heat, about three times gas, or 3.9p per m² per hour for a 150W/m² mat at full power.

The floor doesn’t make heat. Your boiler or heat pump does, and underfloor heating only saves money because it lets that heat source run cooler. That’s worth a lot with a heat pump and very little with a gas boiler. So our position is simple: wet underfloor heating in new extensions and wherever the floor is coming up anyway, well-sized radiators for a whole-house heat pump retrofit, and electric mats only for small rooms used in short bursts.

Is underfloor heating cheaper to run than radiators?

Here’s the comparison at the October–December 2026 price cap. Every assumption is listed underneath so you can redo it for your own home.

The assumptions behind every row:

• Heat demand: 8,000kWh of space heating a year. That’s an illustrative figure, and it’s the same whichever emitter you fit. Scale the answers up or down in proportion to your own home’s demand.
• Prices: gas 7.97p/kWh and electricity 26.32p/kWh, the Direct Debit unit rates in the price cap. Standing charges and hot water are left out because they’re the same whichever emitter you choose. The exception: a heat pump that lets you cap the gas supply also saves the 29.68p a day gas standing charge.
• Gas boiler: 84% efficient at 70°C flow and 89% at 55°C, as measured on a condensing boiler in the Salford Energy House tests for Nesta. Efficiency didn’t rise further at 48°C, so we give underfloor heating the same 89%. The researchers expected it to keep rising and blamed the boiler cycling on and off, so a steadily running underfloor system may do a little better.
• Heat pump: seasonal efficiencies (SCOP) for a 7kW Vaillant aroTHERM plus at each flow temperature, from Vaillant’s installer quick guide. These are lab figures, so treat the gap between rows as more reliable than the totals.
• Electric underfloor: every kWh of electricity becomes a kWh of heat, like any electric heater.

To redo it: yearly cost = heat needed in kWh ÷ efficiency (or SCOP) × unit price. A heat loss survey gives you the real heat demand, room by room, and our savings calculator gives a typical installed cost, saving and payback for a heat pump in your region.

On a gas boiler, flow temperature matters more than the floor

A condensing boiler recovers extra heat only when the water coming back to it is cool. Nesta puts the threshold at a return temperature below 54°C, with more condensing the lower it goes. Underfloor heating returns cool water, so the boiler condenses well. But radiators turned down to 55°C get most of the same benefit: the Salford test found a five-point efficiency gain between 70°C and 55°C flow, and no further gain at 48°C, which the researchers put down to the boiler cycling on and off. That’s why the gas rows in the table land at £716 for both.

Checkatrade’s underfloor heating cost guide reaches the same answer, putting a gas boiler with radiators and a gas boiler with underfloor heating at an identical £1,916 a year in its example. Some suppliers go further: Nu-Heat’s guide says warm water underfloor heating is around 25% more efficient than radiators with a condensing boiler. We can’t find independent test data that backs that on gas. One catch cuts the other way: if the same boiler also feeds radiators at 70°C, the return water warms up and the underfloor gain shrinks.

On a heat pump, underfloor heating earns its keep

Heat pump efficiency falls steadily as flow temperature rises. In Vaillant’s figures the 7kW unit drops from a SCOP of 4.36 at 35°C to 3.91 at 45°C, 3.65 at 50°C and 3.39 at 55°C. Underfloor heating at 35°C uses 10% less electricity than well-sized radiators at 45°C, 16% less than radiators at 50°C and 22% less than radiators at 55°C. On 8,000kWh of heat, that’s £56, £94 and £138 a year.

The MCS Heat Emitter Guide says the same thing with stars. In its worked example, radiators rated at about three times the room’s heat loss reach four stars at 45°C, while screed underfloor heating under tiles reaches the maximum six stars at 35°C. The guide says an aluminium panel underfloor system under tiles can’t reach as high a rating in the same room. Radiators still work well with heat pumps, as our guide to heat pump flow temperatures and radiator sizing explains. And since June 2022, Approved Document L has said any new or fully replaced wet heating system should be sized to run at 55°C or lower (2021 edition, paragraph 5.10).

Electric vs wet underfloor heating running costs

Electric mats are rated per square metre. Warmup’s StickyMat, for example, comes in 150W/m² and 200W/m² versions, the higher one for rooms with high heat loss such as conservatories. At 26.32p/kWh, a 150W/m² mat costs 3.9p per m² for every hour it’s drawing full power, and a 200W/m² mat costs 5.3p. Once the floor is up to temperature, the thermostat switches the mat on and off, so it draws power for only part of each hour.

Assumptions: 150W/m² mats, the 26.32p/kWh price cap rate, and a heating season of October to March (182 days). The share of time drawing power is our assumption, not a measured figure; a cold floor or a poorly insulated room pushes it up. Put the same 1,638kWh of heat that the extension uses into wet underfloor heating and it costs about £147 on a gas boiler or £99 on a heat pump.

So electric underfloor heating is fine for a bathroom on a timer and poor value as the main heat for a large room. For bathrooms, compare it with a heated towel rail.

What does underfloor heating cost to install?

Checkatrade’s June 2026 figures, supply and fit:

• Electric underfloor heating: £50–£75 per m² in a new build, £60–£85 per m² in a renovation.
• Wet underfloor heating: £85–£100 per m² in a new build, £95–£110 per m² in a renovation.
• A 90m² semi-detached house: £4,500 electric or £7,650 wet as a new build, and £5,400 electric or £8,550 wet as a retrofit.
• For comparison, wet heating pipework and radiators come to about £3,000 in Checkatrade’s example, excluding the boiler.

Checkatrade also suggests setting aside an extra 10–15% for preparation and finishing, such as insulation boards, levelling and trimming doors.

How disruptive is retrofitting underfloor heating?

It depends which system goes down. A traditional screed system needs a minimum of 65mm of hand-mixed screed or 50mm of liquid screed, according to Nu-Heat. Hand-mixed screed dries at roughly a day per millimetre for the first 50mm, and Nu-Heat calls four weeks a sensible minimum. That’s a job for an extension or a gutted ground floor.

Low-profile overlay systems sit on the existing floor. Nu-Heat’s thinnest adds as little as 15mm, and its low-profile range stays under 22mm, though doors and thresholds may need trimming. Electric mats barely raise the floor: the StickyMat wire is 1.8mm thick and goes into the tile adhesive. Checkatrade says an electric system in a single room usually takes one to two days and a wet system on a single floor two to five days, plus drying time for any screed. Electrical work in bathrooms may need a qualified electrician and Part P compliance.

How quickly does each system heat up?

Nu-Heat says a typical screed system run by a boiler takes about an hour to heat up, and that screed takes longer to warm but holds heat much longer. Its low-profile systems heat up about as fast as a radiator. So screed suits steady running through the day, and it’s a poor match for heating a room for an hour in the evening.

Radiators slow down too when you turn the flow temperature down. In the Salford test, the house took 30 minutes to warm up in the morning at 70°C flow and 56 minutes at 55°C. Low-temperature heating of any kind rewards longer, gentler running.

Which floor coverings work with underfloor heating?

Tiles and stone pass heat best. Nu-Heat’s floor covering guide quotes heat outputs of 71W/m² under tiles, 68W/m² under vinyl, 56W/m² under wood and 48W/m² under 2-tog carpet. A lower output means the water has to run warmer to heat the same room, which costs efficiency on a heat pump.

• Carpet: the carpet and underlay together should not exceed 2.5 tog, and preferably stay under 1.5 tog with a heat pump (Nu-Heat).
• Wood: engineered boards cope better than solid timber, and timber should acclimatise in the house before it’s fitted.
• Vinyl and LVT: Nu-Heat sets a 27°C maximum floor temperature and recommends a floor sensor to cap output. BS EN 1264-2 limits floor surface temperature to 29°C in any case.

That surface limit caps how much heat a floor can give. If a room loses more heat per square metre than the floor can supply, it’ll need a radiator too, and only a room-by-room heat loss calculation tells you.

Underfloor heating or radiators: our verdict by situation

New extension

Wet underfloor heating. The floor is being built anyway, so at Checkatrade’s new-build rate of £85–£100 per m² a 25m² extension costs about £2,125–£2,500 for the system. On a gas boiler it won’t cut your bill much. Buy it for comfort and free walls, and because it’s ready for a heat pump. Our guide to insulating an extension covers the floor insulation it sits on.

Kitchen

If it’s a kitchen-diner with the floor coming up, run wet underfloor heating from the main system. If you’re only re-tiling a small kitchen and want warm feet, an electric mat is fine at roughly £172 a season in our example. Don’t make it the kitchen’s only heat.

Whole-house heat pump retrofit

Radiators, upsized where needed so the system runs at 45°C. Underfloor heating at 35°C would save about £56 a year on 8,000kWh of heat, while wet underfloor heating in a 90m² semi costs about £8,550 as a retrofit. That never pays back. Put underfloor heating only on floors you’re digging up for other reasons. Our guide on whether heat pumps need new radiators covers the sizing, and in England and Wales the £7,500 Boiler Upgrade Scheme grant goes towards the heat pump itself.

Bathroom

An electric mat on a timer. At Checkatrade’s renovation rate a 4m² floor costs about £240–£340 to fit, it adds almost nothing to the floor height, and it costs about £57 a season on for two hours a day. Tiles suit it best anyway.

Weighing up a heat pump with underfloor heating or radiators? Request a free quote and up to three approved installers who cover your area may contact you. No charge, no obligation.

We compare published specs, prices and test data rather than testing heating systems ourselves, and every figure here was checked in September 2026.

FAQs

Is underfloor heating cheaper to run than radiators?

On a gas boiler, barely: both cost about £716 a year for 8,000kWh of heat if the radiators run at 55°C. On a heat pump, yes: wet underfloor heating at 35°C costs about £483 against £539–£621 for radiators at 45–55°C.

Is underfloor heating expensive to run?

Wet underfloor heating isn’t; it costs the same or less than radiators on the same heat source. Electric underfloor heating is expensive as main heating, at 26.32p per kWh of heat against about 9p from gas and 6–8p from a heat pump.

Is underfloor heating more efficient than radiators?

Not in itself. It lets the heat source run cooler. With a heat pump that means 10–22% less electricity than radiators at 45–55°C on Vaillant’s lab figures. With a gas boiler the measured gain is about five points of boiler efficiency, and only if your radiators currently run hot.

How much does electric underfloor heating cost per hour?

About 3.9p per m² per hour at full power for a 150W/m² mat, or 5.3p for a 200W/m² mat, at the October–December 2026 price cap rate of 26.32p/kWh. Once the floor is warm, the thermostat cuts the actual draw.

What does wet underfloor heating cost compared with electric?

Checkatrade puts wet systems at £85–£110 per m² and electric at £50–£85 per m², so wet costs more to fit and far less to run. For a 90m² semi retrofit, that’s about £8,550 wet against £5,400 electric.