Then what exactly is the spray product that many suppliers are claiming is a radiant barrier spray paint that is designed to be applied directly to the underside of the roof decking? If the product blocks 75% or more of the radiant heat, it’s actually called an “interior radiation control coating (IRCC)” If it blocks anything less, it’s just a paint.
Why are IRCC spray suppliers misnaming their products as radiant barriers? Because radiant barriers are the most effective product at blocking radiant heat and lowering monthly utility bills. In essence, these spray paint suppliers are piggy-backing on the rising success and notoriety of radiant barriers.
Fact: True radiant barriers outperform all IRCC paint products.
At this time, the most effective IRCC spray product, Heat Bloc-Ultra, claims to only blocks 80.5% of the radiant heat whereas the best radiant barriers block up to 97%. And considering the technique used in spraying on such a paint, reflectivity results can vary based on many factors:
- how evenly and thickly is it applied,
- how adequate the coverage is (whether gables, rafters, and all other areas that emit heat are covered), and
- whether the coating has been watered down to extend the coverage (yes, some suppliers actually do this), etc.
For a recent comparison of IRCC products, please see this coatings study performed by R&D Services for the Reflective Insulation Manufacturers Association (RIMA).
A radiant barrier, as defined by the American Society for Testing and Materials (ASTM), is a product which reflects/blocks 90% or more of the radiant heat. Most radiant barriers block up to 97% of the radiant heat; much more than the best IRCC on the market.
Fact: Radiant barriers are more economical than IRCC paint products.
On average, the cost of a so-called radiant barrier paint product is about 30¢ per square foot and that doesn’t include labor costs. IRCCs typically require an expert to install with professional equipment (power sprayer, installation garments including full suit, face mask, and gloves, etc) in order to get the necessary coverage.
On the other hand, a quality radiant barrier will cost an average of only 13¢ per square foot and can be installed by the homeowner if they are handy and comfortable being in the attic space. Of course, an installer can be hired to install a radiant barrier as well but labor costs are much less for installing a radiant barrier since no specialized equipment is needed.
Don’t waste money on a less effective spray product when a radiant barrier costs less and saves you more on your monthly utility bills.
© 2010 Radiant Barrier Journal | RadiantGUARD.com