nderfloor heating warms the entire surface of the floor. Even in a small room, this is a large radiant surface, which means that the heat running through the heating elements only need needs to be slightly hotter than the room. By contrast, a radiator transfers heat from a very small surface and has to be much hotter than the room it is heating. Typically, the temperature of the water in an underfloor heating system pipe 45-65 degree centigrade compared to the 80 degrees centigrade of a radiator.