Underfloor heating at home

Underfloor heating warms a room from the floor up. Some people fit it in a new extension, and others add it when they renovate a room.

This page covers the two main kinds, how each one works with the rest of a home's heating, and the building rules that apply in England.

Wet and electric systems

A wet system circulates warm water from a boiler or heat pump through pipes in the floor. An electric system uses heating cables laid in the floor instead.

BEAMA, the trade association for underfloor heating makers, says wet systems work with gas, oil and LPG boilers. They also work with air source and ground source heat pumps.

Running costs

What a system costs to run depends on the fuel it uses and on the unit rates in each household's tariff. Ofgem, the energy regulator, explains how unit rates and standing charges work.

BEAMA says a wet system costs less to run than an electric one, because electricity costs more than gas or oil. It also says wet systems are more efficient than radiators, because they run at lower water temperatures.

Heat pumps and water temperature

Building rules in England now look for heating that runs on cooler water. Where a wet heating system is newly installed or fully replaced, Approved Document L says it should be sized to heat the home with water at 55°C or lower.

Underfloor heating spreads its heat across the whole floor, which helps it work at these lower temperatures. In England and Wales, the Boiler Upgrade Scheme gives grants towards replacing oil, gas, electric or LPG heating with a heat pump. GOV.UK suggests asking an MCS certified installer whether a home suits a heat pump.

Floors, insulation and controls

Approved Document L sets out what a new underfloor heating system in a home in England should have.

Controls to adjust the operating temperature.
A manual override on the room thermostats of an electric system.
An automatic lower temperature at night or when the room is empty, where the screed is more than 65mm thick.
Insulation under the system, to limit the heat lost downwards.

For a direct electric system, the cables go in a screed no more than 60mm thick. BEAMA says carpet, wood and tile can all go over underfloor heating. Some pass heat better than others. A correctly designed system still reaches the room temperature it needs on all of them.

Renovations and single rooms

BEAMA says slim systems can go over an existing floor in a renovation, without major disruption. A single room can have underfloor heating while the rest of the house keeps its radiators. Screed systems take longer to warm up than slim ones.

Approval and installers

In England, installing or replacing a heating system can need building regulations approval. So can changing electrics near a bath or shower. Householders do not need to get approval themselves if they use an installer registered with a competent person scheme. Building regulations approval is separate from planning permission.