R-values relate more to mass type insulations or insulating materials that are installed in an enclosed air space. Radiant barriers are typically designed to work in vented attics, so their performance is not rated with an R-value; however, R-values are not the ONLY way to quantify resistance to heat flow. For example, a tree or an awning doesn't have an R-value, but it certainly can keep you cool. To simply put it, a radiant barrier is like putting a shade tree in your attic. Technically speaking, Silver Shield™ Radiant Barrier reflects 97% of the radiant heat and only emits 3% into the attic so unlike R-value, the lower the "E-value", or the less that it radiates into the attic, the better the radiant barrier. Silver Shield™ is the best-rated radiant barrier on the market.
Attics & Ceilings