Modern underfloor heating systems systems work by passing low temperature hot water around a network of pex pipes installed in the floor. Each room or zone is fitted with a continuous length of pex pipe with the flow and return connected to a centrally located brass or copper manifold.

In a conventional radiator system the surface area of the radiator and the average temperature of the water flowing through it determines the heat output, therefore, for a given radiator size, the output can be varied by changing the mean water temperature.

This is the principle applied to underfloor heating where the size of the emitter, in this case the floor, is so large that the water temperature (usually around 45°C) can be reduced to well below that commonly used in radiators and still provide the required heat output.

The diameter and spacing of the pex pipe, the floor construction and the floor finish also influence the heat output from the underfloor heating system.

PEX - high density cross-linked polyethylene, 16mm x 2mm OD with oxygen diffusion barrier. BS7291, Part 1 & 3:1991, DIN 16892, DIN 4726

While radiators heat the room by convection (movement of air), underfloor heating works by radiant heat, so instead of heating the air surrounding objects it heats the objects including people eliminating any uncomfortable hot and cold air flows around the room.

Radiant heat dissipates from the floor about 3 metres reducing wasteful build up of heat at the ceiling especially in areas with high ceilings.