Abstract: A method for installing a radiant barrier in a building, particularly on an attic floor, is carried out by randomly distributing shreds of a thin, reflective foil in an attic space to form a bed of foil shreds on the attic floor. The foil shreds reflect longwave radiation and thereby provide a radiant barrier which reduces radiant heat transfer in the attic space. An insulating material useful in such a method includes a bat of insulation disposed, for example, on an attic floor, and a bed of reflective foil shreds covering the layer of insulation.