Electric underfloor heating vs gas: what costs more?

You want a warm floor in the bathroom, the kitchen or maybe the whole living room. Then the question soon comes up: electric underfloor heating, or a wet system running off the gas boiler? And more importantly: which is cheaper to run?

The honest answer: per unit, electricity is far more expensive than gas, roughly three times as much in the UK. But that doesn’t automatically make electric underfloor heating the expensive choice. Here are the numbers, using the current Ofgem price cap.

Per kWh, electricity costs more

Electric underfloor heating turns all the electricity it uses into heat. One kWh of electricity gives you one kWh of heat. Under the Ofgem price cap for October to December 2026, electricity costs 26.32p per kWh, so that is also what a kWh of heat costs you.

Gas is capped at 7.97p per kWh. A modern condensing boiler turns about 90% of that into useful heat, so a kWh of heat from gas costs around 8.9p.

That makes electric heating about three times as expensive per unit of heat. You may hear that electric underfloor heating is “100% efficient”. That is true, but a condensing boiler only loses around 10%, so it doesn’t close the price gap.

Why electric is still often the smarter choice

What you pay per kWh is not the same as what you pay over a year. Three things make the difference.

Much simpler to install

A wet underfloor system needs pipework back to the boiler, a manifold, often a pump and mixing unit, and a heating engineer. Usually the screed has to come up or be channelled out. Electric underfloor heating is a heating mat just a few millimetres thick that sits directly under the tiles and connects to the mains. No plumbing, no digging out floors. Many people lay the mat themselves using our installation guide. In a bathroom, the electrical connection is notifiable work, so have it done or signed off by a registered electrician.

No servicing

A gas boiler should be serviced every year, which typically costs around £80 to £120. Electric underfloor heating needs none of that. No moving parts, no water, no leaks.

Heat only where and when you want

This may be the biggest difference. Want a warm bathroom floor in the morning? With electric, you heat just that one floor. And because it responds quickly, you only switch it on shortly before you get up. With a Wi-Fi thermostat you set a schedule, so you only pay for heat you actually use.

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So which is cheaper: gas or electric?

We worked out three situations for a heating season from October to April (212 days), assuming full-power heating hours, electricity at 26.32p and gas at 7.97p per kWh (condensing boiler, 90% efficient).

Worked example, excluding standing charges.

In the bathroom, electric costs you about £56 a year more. Spread over the heating season, that is around £8 a month. For that, you avoid running pipes to the boiler and the disruption that comes with it. In a bathroom, electric is often the smartest choice.

In the kitchen, the gap grows to about £167 a year. Noticeable, but a schedule and good insulation bring it down considerably. A large living room heated entirely by electric is a different story.

Bonus: no gas supply, no gas standing charge

Planning a home or extension without gas at all? Then you also avoid the gas standing charge. At 29.68p per day under the current cap, that is over £100 a year, which shifts the sums in favour of electric, especially for smaller areas.

But for the whole house, electric doesn’t win

If you want to heat large areas or the whole house with direct electric heating, costs add up quickly. In the living room example you pay over £650 a year more than with gas. In a poorly insulated home, even more.

For the whole house, a heat pump with wet underfloor heating is usually the most economical option. It turns one kWh of electricity into roughly three to four kWh of heat. The upfront investment is considerably higher, although government grants can help.

On carbon, the UK grid has become much cleaner over the past decade. Direct electric heating is therefore often lower in carbon than a gas boiler, and that advantage grows as the grid decarbonises further.

When is electric cheaper than gas?

On a standard variable tariff, a unit of heat from electricity is always more expensive. But there are situations where that flips.

With a time-of-use or agile tariff

With a smart meter, you can choose a tariff where the price changes by time of day, or even every half hour. When it is windy or sunny, prices drop, sometimes close to zero. Whenever electricity costs less than about 8.9p per kWh, heating with electric is cheaper than gas at that moment.

Handy: a floor in tile adhesive or levelling compound holds on to heat for a while. Heat during cheap periods and you still benefit afterwards. Be aware that in midwinter, very cheap periods are less frequent.

With your own solar panels

If you use electricity from your own roof directly, it only costs you what you would otherwise have earned by exporting it. Smart Export Guarantee rates are usually well below what you pay for imported electricity, so using it yourself makes sense.

To be fair: solar panels produce little in winter. This works mainly in spring and autumn, during the day.

As policy shifts costs away from electricity

Government policy is gradually moving costs away from electricity bills to make electric heating more attractive. That should narrow the gap with gas over time.

How to keep electric underfloor heating economical

Going electric? There is a lot you can do to keep consumption down. Start with insulation under the heating. Without it, part of the heat disappears into the subfloor. With insulation boards, the heat goes up, exactly where you want it. Read more in Insulation under electric underfloor heating: is it necessary?

Also choose an output that suits the room. In a well-insulated room, a 100 watt per m² set is often enough. For a bathroom or tiled floor that needs to warm up quickly, go for the Pro-Series at 150 watts per m². And no, a higher output doesn’t automatically mean a higher bill: the floor warms up faster, so the thermostat switches off sooner.

Finally, don’t set the temperature higher than you need. Find the right settings in Best temperature for bathroom underfloor heating, or browse all complete sets.

Conclusion

Look only at the price per kWh and electric underfloor heating is clearly more expensive than gas. That changes once you factor in installation, servicing and how you use it. Heating a single room such as a bathroom, cloakroom or kitchen? Then the extra running cost is modest and you save a lot on installation. Electric is often the smartest choice, especially combined with a smart thermostat, a time-of-use tariff or your own solar panels.

Want to heat the whole house? Then gas is cheaper to run, and a heat pump cheaper still.

In short: electric heating costs more per kWh, but not necessarily overall. It depends on where and how you use it. Still not sure? Get in touch and we’ll be happy to help.