How Does Underfloor Heating Work?

An Underfloor Heating System warms the floor structure, then the floor surface which in turn warms the room. The main method of heat transfer is by radiation from the floor surface which accounts for about 60% of the system output, the remainder being made up from a combination of conduction and convection. As the majority of heat output is radiant, underfloor heating is very effective at producing comfort at lower air temperatures than conventional central heating systems can achieve. A well designed and installed system heats the occupied zone from the floor up and gives rise to almost none of the temperature stratification of a conventional space heating system. This is one factor that allows underfloor heating systems to be more fuel efficient as high temperatures at ceiling level are not produced.

The basic principle of operation of an underfloor heating system is that warm water is circulated through pipes which are embedded in the floor structure. As the floor is a large area compared to a traditional radiator, the floor surface temperature can be quite low, usually between 22 & 28 degrees C.

Generally hard floor finished such as ceramic tiles, slate and stone work best with underfloor heating but laminates, timber, carpet and vinyl can all be used with great success so long as any underlay used with carpets, timber or laminates has as low a tog value as possible i.e. it is not insulating.

A well designed underfloor heating system need not cost the earth, indeed it will help reduce energy bills by around 15 – 40% compared to the equivalent radiator system.