This 40mm durable rigid panel is specifically designed to achieve exceptionally high thermal values, making it the ideal product. Unlike traditional bulk insulation and blankets, Foilboard Green rigid panel will not shrink, sag or droop, ensuring that the building performs to its optimal thermal value from day one, to year 25 and beyond. Foil Insulation works by using the basic laws of heat and cold to its advantage in order to insulate a building. Once installed, reflective foil insulation panels create a barrier between the inside of a property and the external environment. In the case of a hot day, foil insulation panels will reflect heat back out and away from a building, preventing it from getting too hot.