In the attic, where is the best place to install radiant barrier?
One problematic technique is to put radiant barrier directly on the underside of the roof sheeting. What happens in any attic that is not extremely well ventilated is that the surface of the radiant barrier gets very hot and the heat is conducted and convected into the air of the attic causing the attic and its insulation to get quite hot. Then once the sun goes down and the heat wants to radiate out of the insulation, it is reflected back by the radiant barrier trapping this unwanted heat for hours. To see the results of this type of application, click here. Further, any application of radiant barrier up at the roof deck has little or no savings or impact on comfort during winter months. One other consideration is the overheating of shingles. Shingle manufacturers are now limiting or voiding warranties where RBS is installed under the roof decking.
