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Rethinking Cool Roofing Evaluating effectiveness of white roofs in northern climates by Craig A. Tyler, AIA, CSI, CDT, LEED AP All images courtesy Carlisle Construction Materials THE USE OF WHITE, REFLECTIVE ROOFING MATERIALS THROUGHOUT THE UNITED STATES HAS GROWN IN POPULARITY IN RECENT YEARS, BUT ARE THESE ASSEMBLIES REALLY IDEAL FOR ALL LOCATIONS? These types of roofs are increasingly specified, spurred by voluntary green building rating programs such as the U.S. Green Building Council’s (USGBC’s) Leadership in Energy and Environmental Design (LEED), along with codified systems such as the American National Standards Institute/Cool Roof Rating Council (ANSI/CRRC) 1-2010 Standard used in California’s Title 24. Many of these initiatives and codes rely heavily on research completed at the academic level with computer models and the results of tests performed to determine a material’s solar reflectance and thermal emission. The result of the models and tests have shown using a reflective material yields net energy savings between the warm summer months and colder winter months in many areas of the country. However, under initiatives such as LEED, the building’s geographic location is given the same weight or value to the cool roofing, whether it is in Miami or Minneapolis—despite the fact these two locations have very different climates. Research on the value and benefits of cool roofing is continuing within the industry, which is indicative cool, reflective materials still may not be the panacea of energy savings some are currently marketing. With this in mind, it is increasingly important for architects, specifiers, engineers, and design professionals to rethink use of cool roofing in every climate, especially northern regions. Energy costs When properly designed and installed, reflective roofing materials can reduce building cooling costs during warm summers by ‘bouncing’ ultraviolet 44 the construction specifier | november 2013 CS_November2013.indd 44 2013-10-16 11:29 AM