What is the R-value of radiant barrier?
This question is often asked and is an indication that there is still some confusion between radiant barriers and reflective insulation. Radiant barriers are always installed with the reflective, (low emittance), surface facing an open air space. Because of a radiant barriers low emittance and high reflectance, it can block about 90 97% of the radiant heat that strikes the surface, significantly reducing the total heat transfer in and out of a building. However, due to variations in building construction, location and climate – one cannot assign a unique R-value to this application. Calculations can and have been made for very specific applications, but every given application requires its own evaluation. Will radiant barriers cause roof shingles to deteriorate? Testing done by the Florida Solar Energy Center has shown that roof shingle temperatures do increase between 5 and 10F when radiant barriers are installed under the roof deck. The color of asphalt shingles has more of an effect
