Buildings heat mostly from radiant heat sun roof and walls. Conduction draws heat into structure. Using heat reflective insulation, radiant heat reflected before can penetrate heat reflective coating. The whole building will remain cooler. Raises questions about effectiveness roof vents, roof ducts, vent ridges, whirlybirds that can only duct out some hot air, that now coming through any roof, walls that are not protected by reflective insulation.