Abstract
Some guidelines for improving the energy efficiency of roofs and attics are presented and are based on the research of the DOE Building Technology. The results of combined analytical and experimental studies were used to benchmark computer tools, which in turn, were used to simulate homes in hot and cold climates. Adding floor and roof insulation, above deck ventilation, radiant barriers, cool color shingle, metal or tile roofs, sealing the attic floor, sealing the duct system and sealing the attic were simulated to compute the cost of energy savings. Results are prioritized to help building owners make an informed economic decision when contemplating roof and attic retrofits. Sealing the attic floor is a top retrofit option. The sealed attic approach and a new prototype roof assembly an “insulated and ventilated roof” are good options for retrofit work but have paybacks ranging from 15 to 25 years. A new sealed attic concept was simulated and computations show its simple payback is about 10 to 12 years in hot and cold climates; its first cost is significantly reduced from that of a spray foam approach. For new construction the best option is to keep the ducts out of the attic, make sure the attic floor is sealed and add at least code level of insulation to the ceiling.
