Lets start with the science behind radiant barriers. Heat penetrates buildings in 3 ways: conduction, convection, and radiation. Our main focus of this article will only focus on radiation, which is defined as the transfer of heat by electromagnetic waves known as thermal radiation. Thermal radiation is a form of invisible light that travels through the air from a warm to a cool surface. Warm surfaces, such as roof decks warmed by sunlight, will radiate or emit their heat to the cooler interior building surfaces in the attic.
A byproduct of the space industry, Radiant heat barriers address radiated heat flow by placing a low-e (low energy transference) material in the path of thermal radiation, blocking heat transfer, reducing the amount of heat buildup in the attic and also reducing the cooling load on your HVAC system.
Radiant barriers work best when coupled with other weatherization measures such as attic ventilation, and attic insulation and can often compound the savings experienced; for example studies have shown that a radiant barrier can increase the R-value of attic insulation by as much as 95%!
Emissivity is the ability of a surface to radiate energy; typical wood decking used on almost every roof has an emissivity factor .90, meaning once heated to surrounding temperatures it transfers 90% of the sun's heat applied to it, by radiation..into your attic space! Using a radiant barrier reduces the emissivity of wood decking to .25 or lower; meaning only 25% or less of the sun's heat is transferred into your attic! This works well for keeping heat in during the winter months too, studies show that a 15% reduction in heat loss through the attic with radiant barrier. Starting in 2006, local building codes across the country began including radiant barrier as a code requirement for roof replacements and new construction.
Radiant barriers come in many forms, such as pre-manufactured sheets of foil-faced decking for new construction, or rolls of film or spray-on for retrofit applications. Any of these products can lower your energy usage in your home while making your living space more comfortable. Call Fox Service Company today or click here for a FREE ENERGY AUDIT and ask how radiant barrier and our other weatherization measures can help you 'weather the storm'! 512 442 6782 or email us directly at Reshvac@foxservice.com
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