New Literature Review on Cool Roofs, UHIE, and Energy Efficiency
ERA recently commissioned a literature review, working with the Department of Construction Science and Management at Clemson University. This literature review conducted a thorough investigation of published data and models designed to understand the impact of membrane color on cool roof efficiency. The macro-level literature review investigated almost two thousand published articles, winnowing down the published literature to 102 papers deemed appropriate for more intense review. Key words for inclusion in the study included “cool roof”, “energy efficiency”, “urban heat island effect” and “life cycle”. According to the Clemson researchers, this exhaustive literature review exposed the reasons that there is no clear answer about the relationship of UHI and energy efficiency. First, the results of these studies varied because the impact of cool roofs is influenced by a range of factors such as roof type, climate, and location. The studies also varied in methods of data capture and analysis, reliance on simulation-based studies and minimal data capture duration. Other factors potentially influencing varying outcomes included consideration of a “heat penalty” during the winter season and the interaction of different building heights. Additionally, there was no consistent comparison of the Impact of urban tree canopy, roofs, hardscape, asphalt surfaces, and insulation thickness. “In many instances”, according to Dr. Dhaval Gajjar, a primary researcher on the project, “more recent studies based their conclusions and recommendations on widely distributed prior studies, which now must be considered dated or incomplete information given more updated research.” An overview of the research project may be seen in the pdf link at the top of the page.