When installing an underfloor heating system, it is important that sufficient thermal insulation is provided below the pipework to minimise downward heat transmission.

The Building Regulations dictate the required U value of the floor, which currently should not exceed 0.25W/m2 for the elemental method. The minimum required thickness of the insulation will depend on its thermal property, and on the construction of the floor.

The pipe fixing floor panel can be included in the U value calculation, its base consists of a 20mm thick expanded polystyrene sheet, and the technical properties are given in the Installation section, Step 4.