ERA | EPDM Roofing Association

Calgary Says No to Cool Roofs

Calgary Says No to Cool Roofs

May 18, 2015 15:25

 A recently released study of the energy efficiency of white roofs is adding to the growing evidence that there is a significant “energy penalty” associated with the use of “cool roofs” in cold climates.

The study "Sustainability of Rooftop Technologies in Cold Climates" was conducted by researchers at the University of Calgary and published in The Journal of Industrial Ecology, compared “the environmental performance on a life cycle basis of white roofs, green roofs, and roof-mounted PVs”.  While the study noted that white roofs have been an outstanding option in hot climates, their environmental performance in colder climates “is strong affected by the heating penalty”.  In other words, the energy saved in warmer months is more than offset by the increased energy used in colder months because of the solar reflectivity of the roofing membrane. The bottom line according to the study, “. . . net negative environmental impacts lead to white roof technology not being recommended for general applications in cold climates.”

This study reinforces the long-held science-based position of ERA that “one size fits all” mandates which require reflective roofing in cold climates fail to take into account this energy penalty. In addition, ERA leadership maintains that decisions about the choice of a roofing system are best left to owners, architects, contractors and specifiers who can judge the needs of their particular construction project.  For more on the appropriate use of white membrane, and guidance on choosing EPDM for your roofing needs, go to http://www.epdmroofs.org/epdm-todays-choice/epdm-roof-for-every-climate.

Ellen Thorp



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