How does reflective foil insulation and radiant barriers keep heat in in the winter and help keep heat out in the summer?
A great example of stopping heat transfer in hot and cold temperature is the Thermos Bottle. Radiant barriers and reflective foil insulation in conjunction with other insulation types creates the same effect. Conductive and Convective heat transfer is slowed by the airspace and tight seal. Radiant heat is slowed by the reflective surfaces. Whether the Thermos Bottle starts off hot or cold does not matter because the all forms of heat transfer have been contained.
