For use with the Warmup Foil underfloor heating system, this insulated underlay has been specially developed to make your heating system more efficient and effective.Sitting between the cold subfloor and foil heater, this underlay reflects heat upwards, improving the effectiveness of your underfloor heating system. With a grooved polystyrene top layer, the silver foil backing acts as an effective moisture barrier.For installation beneath the Dual Overlay as part of a complete stable system, the Warmup insulated underlay is the ideal duo combination for installation of soft and resilient floor coverings such as carpet and vinyl.At just 6mm in depth, it is lightweight and easy to install, creating a highly energy efficient and sound proofed underfloor heating system.