The color of a roof assembly and its correlation to energy efficiency has been a highly debated topic in recent years. Far too often, a white membrane is selected for buildings in northern climates because of the perception that a “cool” white roof is more environmentally friendly than a dark-colored roof.

A study conducted by Ashley-McGraw Architects, PC and CDH Energy Corp. analyzes this issue and concludes that in northern climates, dark-colored roofing is more energy-efficient and cost-effective than white roofing when heating and cooling costs are examined. The study, Comparative Roof Testing at Onondaga Correctional Facility, found that while the reflectivity of a white roof does help keep a building slightly cooler during the summer months, its negative impact on wintertime energy usage and heating costs is more significant than its cooling cost benefits.

Installing a dark-colored EPDM membrane is valuable in helping to keep a building warm during the heating season.

The study found that, in two identical, side-by-side buildings during the heating season, the thermal heat loss of white roofing was 30% higher than that of dark-colored EPDM roofing, and the building with the white roof experienced 30% greater heating costs than the building with the black EPDM system. The solar absorption of a dark-colored membrane is valuable in helping to keep a building warm during the heating season. The study also found that the summertime cooling cost savings offered by white roofing do not outweigh the increased heating bills in the winter months.

Many factors should be considered when choosing an appropriate roofing system, including UV, hail, and condensation resistance. As a manufacturer of both white and black roofing membranes, Carlisle remains an advocate of selecting a membrane color based on a number of factors, including building type, building use, and geography. It appears that selecting a dark-colored EPDM membrane reduces heating consumption in northern climates and is energy-efficient, cost-effective for building owners, and good for the environment.

For information on EPDM roofing systems, visit www.carlislesyntec.com or contact Ron Goodman at ron.goodman@syntec.carlisle.com.