An Evaluation of the Placement of the Placement of Radiant Barriers on their Effectiveness in Reducing Heat Transfer in Attics

Experimental tests were conducted to measure the influence of radiant barriers and the effect of the radiant barrier location on attic heat transfer. All the tests were conducted in an attic simulator at a steady state. The heat flux through the attic floor was measured at two different roof deck temperatures (120°F and 140°F). The temperature distribution within the base fibrous insulation was also measured. Three different solid kraft laminates with aluminum foil backing were tested. There was a 34 percent reduction (sample A) in heat flux through the ceiling for the case where the radiant barrier was placed 6 inches below the roof deck in addition to the base fibrous insulation (R-11), with the roof deck at 140 F. The reduction for the same sample with the radiant barrier placed on the studs of the attic floor was 46 percent. For all the three samples, the heat flux through the attic floor was reduced when the radiant barrier was placed on the attic floor studs