By Steve Rizer
A final version of a calculator that is designed to assist roofing professionals in measuring the energy and environmental benefits of modern roof system technologies should be available by year’s end, Jim Hoff, the Center for Environmental Innovation in Roofing’s vice president of research, told ConstructionPro Week. The RoofPoint Energy and Carbon Calculator is expected to offer the roofing industry an opportunity to deliver tangible data on the value of roof systems to building owners who are concerned with the environmental impacts of their building portfolios.
Hoff previewed the tool last month at the 28th RCI International Convention and Trade Show in Orlando, Fla. During his presentation, he explained how the RoofPoint rating system was used as a template to develop a comprehensive modeling tool to measure the energy-related benefits of sustainable roofing systems, including energy savings and atmospheric carbon reduction. RoofPoint is a voluntary, consensus-based green rating system developed by the center to provide a means for roofing contractors, designers, and building owners to select roof systems based on long-term energy and environmental benefits. The calculator is expected to help quantify the value of RoofPoint.
The presentation addressed energy and carbon savings data for model buildings generated using the calculator. The presentation also included a look at how the calculator can be applied to various roofing projects in different climates and locations.
In a paper submitted to the conference, Hoff acknowledged that several features of the calculator may merit additional refinement to improve accuracy. “Solar thermal calculations currently are based on a national average for solar thermal units in a variety of climates, but the calculator would be much more accurate if a tool similar to PVWatts could be utilized to provide a local solar intensity factor for estimated energy output. In a similar manner, daylighting calculations could be improved significantly through the integration of a more sophisticated daylighting tool that could better quantify the potential heat gain/heat loss offsets associated with different daylighting technologies. Finally, carbon-offset calculations could be refined by developing a model that can accommodate regional variations in energy sources, especially in regard to the ratio of renewable to non-renewable source energy.”
Beyond specific refinements in existing algorithms, the value of the calculator also could be improved by adding embodied energy inputs, Hoff wrote. “Although the calculator currently models only operating energy inputs, all building materials and the installation and maintenance of these materials involve embodied energy inputs in addition to operating energy. As methods such as life-cycle assessment expand in the marketplace and begin to provide accurate embodied energy estimates for common roofing materials, these energy inputs could be added to the calculator.”
