No free lunch
Reflective insulation or Radiant Barriers are designed to block RADIANT (infrared) heat. It has NO R-Value*, and does NOT insulate against Conductive nor Convective heat. Reflective Barriers should be specified according to their Reflective and Emissive ratings, which are used to measure the effectiveness of reflector against radiant heat. A high Reflective value helps block more radiant heat, and a low emissive value means the insulating material releases less of the heat that it absorbs. The often quoted R-Values, are actually EQUIVALENT R-Values.** This specific product appears to be a Reflector combined with a thin “bubble” insulator, which does have some conductive insulation values. Bubble pac is not, however, mechanically durable, and should only be installed (if at all) within mechanically protected cavities (ie: between wall studs & sheathing). * The U-Value is the rate of heat flow in BTU'S in one hour through one sq. ft. area of exposed surface, including insulation (if any) resulting from a 1 degree F. temperature difference between the air inside and the air outside. U = BTU's flowing in One sq. ft. for One degree change. The R-Value is the reciprocal of U - in other words, 1/U. The smaller the U factor fraction, the larger the R-Value, the better the conductive insulation. ** The RE - Value is the equivalent heat stopping ability of Reflective Foil Insulation and Radiant Barriers as compared to Fiberglass, Cellulose and Foam insulation, i.e.: mass insulation’s under identical conditions within a system. Sorry, no free lunch..
