Underfloor heating: how it works, types and installation

Underfloor heating turns the floor into a low-temperature heat emitter. In a water system, a boiler or a heat pump heats the water in a closed circuit, which a manifold sends through pipes under the floor; in an electric system, heating cables or mats provide the heat. The warmth rises evenly across the whole room.

Water systems need more works and a larger upfront investment, but they cost less to run, especially with a heat pump, and they can cool in summer. Electric systems go in with a thinner build-up and cost less at the start, but they use more electricity and only heat. Water suits whole homes; electric suits bathrooms or individual rooms.

Yes, if it is water-based and connected to a reversible heat pump, air-source or ground-source: in summer cool water runs through the same pipes. The temperature has to be controlled so it never reaches the dew point, to avoid condensation. The cooling is gentle and does not dehumidify, so it is sometimes combined with air conditioning. Electric systems do not cool.

It depends on the floor area, the type of system (water or electric), the heat source, whether it is a new build or a refurbishment and the controls you want in each room. That is why we do not give a price per square metre without seeing the project: with those details we prepare a tailored, no-obligation quote.

Yes, especially if the refurbishment is already lifting the floor. The available height, the condition of the slab and the thresholds with doors and stairs need checking. Where height is tight there are low-profile systems, and electric underfloor heating is an alternative for specific rooms. Ideally, decide at the start of the works, before choosing the floor finish.

If the floor is coming up, underfloor heating gives more even warmth, keeps the walls clear and runs at low temperature, which suits a heat pump. Radiators need fewer works and respond faster, better for intermittent use. In a full refurbishment with a new floor, underfloor heating is usually the more comfortable choice; in a partial one, radiators.

Often yes, because a heat pump performs better with the low-temperature water underfloor heating needs and, if it is reversible, it also cools in summer. But it depends on insulation, floor area, use and the prices of electricity and gas. We do not quote generic savings figures: we assess it with the details of your home.

A ground-source heat pump uses the stable temperature underground through a loop of buried pipes and is one of the most efficient sources for underfloor heating, in winter and in summer. In return, it needs a ground collector, with boreholes or buried loops, and a high upfront investment. It makes sense for houses with land, new builds or major refurbishments.

Water systems need the pressure checked, air bled out, the manifold and flows checked and the heat source serviced. Power flushing is done when built-up sludge reduces the flow of water: each circuit is cleaned with pressurised water and a specific cleaning agent, and an inhibitor is added. Electric underfloor heating needs hardly any maintenance.

It is the distributor of a water system: it takes water from the heat source, sends it round the different circuits, usually one per room, and collects the return. It usually sits in a recessed cabinet and lets you balance the flow in each circuit, bleed out air and shut off zones. The thermostats act on it to control each room.

The best option is a programmable thermostat per room or zone that acts on the manifold actuators. Because the floor has a lot of inertia, it is better to programme steady schedules than to switch on and off often. If the system also cools, you need controls with a humidity sensor to prevent condensation on the floor.

Yes. Heating fireplaces include a back boiler or water jacket that heats up with normal use of the fireplace and can feed radiators or underfloor heating, combined with other sources such as gas, heating oil, solar energy, ground-source heat or pellets. For underfloor heating, a buffer tank is usually added to store the heat, along with a mixing valve that brings the water down to the temperature the floor needs.

The best heat conductors are ceramic, porcelain and natural stone. Wood, engineered boards or laminate can also be laid, as long as the manufacturer rates them for underfloor heating and they are thin. Thick rugs and highly insulating floor finishes reduce performance, because they hold back the heat on its way into the room.