Radiant barriers are utilized to reduce summer heat gain in attics. Attics heat up when the sun’s radiant energy heats the shingles and the heat is transferred to the interior attic space through the roofing materials via conduction. The temperature of the attic space increases and that heat is transferred to the building below; increasing summer energy consumption and cooling costs. A radiant barrier can lower that heat transfer, keep the attic space cooler and lower cooling costs by up to 17% in warmer climates.
Radiant Barrier Sheathing
Radiation from the sun is the primary source of heat affecting your attic temperature. Infra-red radiation is augmented by convection and conduction. Convection is when heat is transferred through the air inside the attic and heats the insulation and conduction occurs when heat moves through the insulation to the building below. While heat is radiated and conducted in all directions it always moves from hot areas to cold areas. The hotter the attic, the more the heat moves down to the cooler building below.
The most effective radiant barrier sheathing is a structural roof sheathing panel which consists of an oriented strand board (OSB) with heat-reflecting foil laminated to one side. Other kinds of radiant barriers combine reflective materials (usually aluminum foil) with materials like plastic films, cardboard and craft paper. A radiant barrier must have an emissivity of 0.1 or less to be effective.
Benefits of Radiant Barrier Sheathing
When utilizing oriented strand board (OSB) radiant barrier sheathing, you can reflect up to 97% of solar radiation which translates into an attic heat reduction of up to 30°F.
A cooler attic space means less heat moving to the cooler space below the attic.
Radiant barriers are the most effective in warmer climates, because the hotter it gets the better radiant barriers work.
The reduced attic temperature increases the efficiency of attic ductwork which prolongs the life of your heating and cooling systems because there are fewer cycle times.
In warmer climates your may be able to reduce A/C requirements by up to ½ ton.
Radiant barrier roof sheathing helps to improve comfort in the building interior during the warm summer months and reduces energy costs. Because heat always moves from hot areas to cold areas, radiant barrier sheathing also prevents heat transfer from the warm interior during the cooler winter months.
Radiant barriers may help the home qualify for Energy Star seal and insulate energy efficiency improvement.