US Department of Energy Study Results

Oak Ridge National Laboratory Radiant Barrier Study

In 2013 Oak Ridge National Laboratory published the results of a long-term radiant barrier study that compared 3 different types of radiant barrier in a residential attic* application. The outcome of the study showed that adding a radiant barrier in your attic, stapled across the bottom of the rafters, was the most effective in reducing heat flow (about 50%). Second was utilizing radiant barrier decking with the proper air gap inside the attic space (about 33%) and the third was using a reflective coating in the attic (less than 20%).

Comparing Radiant Barrier Foil, Radiant Barrier Decking and Painted Reflective Barriers in Residential Attic Applications

The official study reports the four attic configurations that were evaluated are: 1) no radiant barrier (control)
2) perforated low-e foil laminated oriented strand board (OSB) deck
3) low-E foil stapled on rafters
4) liquid applied low-emittance coating on roof deck and rafters.

All test attics used nominal fiberglass batting insulation on the attic floor.

Results indicate that the three systems with radiant barriers had heat flows through the attic floor during summer daytime condition that were 32.8%, 49.8%, and 19.1% lower than the control, respectively. Clearly indicating that foil stapled to the bottom of roof rafters has the BIGGEST impact on reducing the heat load into the attic.

SEE THE REPORT

49.8%
lower heat load
& easier to keep cool

Note

The study was not performed in an actual residential attic, but rather in a large scale climate simulator, in order to have complete control over all conditions across the 3 scenarios they were comparing.