Heat dissipation is the movement of heat away from it’s source into the surrounding environment and this can happen by three methods, conduction, radiation and convection. Without heat dissipation the heating wires in underfloor heating would simply heat up without the floor above or the room benefiting from the warmth.
Heat dissipation allows the underfloor heating system to warm the floor and the room and preventing unwanted heat dissipation ensures the heating system runs efficiently. You can prevent unwanted heat dissipation by placing efficient insulation beneath the heating system therefore stopping the heat from being lost downwards.
Conductive heat dissipation is the most significant way heat travels through a solid. As the heating wire gets hot its molecules and atoms start to vibrate rapidly and these vibrations, or heat, are then passed on to the surrounding material. In the case of undertile heating this means the surrounding tile adhesive heats up and then conducts it’s heat to the tiles above. If anyone stands on the tiles their feet will rapidly warm up through conduction between the tile surface and the soles of their feet.
Convective heat dissipation is the main form of heat transfer in a liquid or a gas. As the tiles warm up they heat the air directly above them through conduction as it is in contact with the warm tile surface. As the air heats up it starts to rise due to buoyant convection. Buoyant convection takes place because air expands as it warms up which leads to it becoming lighter. This lighter air rises as the cold, denser air above it falls to take it’s place. With underfloor heating a very large area heats up, the whole floor in fact, so you do not get the draughts caused by radiators.
Radiant heat dissipation does not require any medium to transfer heat, this is the only type of radiation that we receive from the sun through the near-vacuum of space. Thermal radiation is a form of electromagnetic radiation that can pass heat on very efficiently, hence the sun-on-your-back feeling you often get in an otherwise cold environment. With underfloor heating the main form of radiant heat transfer occurs from the floor surface itself. In a room with underfloor heating the entire floor will emit thermal radiation so you will feel the warmth even if you are not standing on the floor and the air temperature is still low. Tiled and stone floors are the most efficient radiators of heat followed be vinyl, linoleum, laminate, wood and finally carpet.