Radiant barrier is the only product on the market that actually blocks radiant heat transfer. Sometimes called reflective foil insulation, EcoFoil is manufactured using pure aluminum that is chemically bonded to a tear-proof scrim poly substrate, making it easy to work with and virtually indestructible. Radiant barrier foil insulation has two properties that give it supreme performance against the transfer of radiant heat. The first property is reflectivity. Reflectivity means both sides of radiant barrier consist of metalized aluminum which reflects or blocks 96% of radiant heat from transferring through the barrier. The second property is emissivity. The emissivity of a material refers to how much heat is absorbed and radiated from its surface. The natural elements of metalized aluminum foil insulation result in a very low emittance of heat energy.