Radiant Barrier

Radiant barriers are materials that are installed in buildings to reduce summer heat gain and winter heat loss, and hence to reduce building heating and cooling energy usage. The potential benefit of attic radiant barriers is primarily in reducing air-conditioning cooling loads in warm or hot climates. 

Radiant barriers work by reducing heat transfer by thermal radiation across the air space between the roof deck and the attic floor, where conventional insulation is usually placed. All materials give off, or emit energy by thermal radiation as a result of their temperature. The amount of energy emitted depends on the surface temperature and a property called the “emissivity”. The emissivity is a number between zero and one. The higher the emissivity, the greater the emitted radiation.