Thermal underlay that prevents heat loss on cold substrates or in electric floor heating applications. Functions as a stable barrier between the cold subfloor and electric heating systems, reflecting both conventional and radiant warmth upward. Achieves a thermal resistance (Rm value) of 0.190 m².K.W.⁻¹. Suits hard flooring types including click laminate, click veneer, and PVC click with HDF backing on cold surfaces.