When you think about an energy-efficient building, you may picture a newly constructed building that meets or exceeds LEED® standards and features many energy-saving bells and whistles. However, there is a great opportunity to save energy by rehabilitating an existing building instead of constructing a new building. In fact, the real savings—in energy and dollars—lie with existing roofs in the U.S., which encompass 50 billion square feet, according to the Center for Environmental Innovation in Roofing.
The Department of Energy (DOE) and other policymaking organizations have established efficiency targets for buildings with the ultimate objective of net-zero energy and emissions. As a result, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Inc. is developing standard 90.1-2010, "Energy Standard for Buildings Except Low-Rise Residential Buildings," with the intention that when a typical newly constructed commercial building is designed to comply with the standard, it will consume 30 percent less energy than buildings complying with ASHRAE 90.1-2004.
According to the National Renewable Energy Laboratory, a typical commercial building would consume more than 70,000 British thermal units (Btu) per square foot (floor area) per year under ASHRAE 90.1-2004, in which case a potential 21,000 Btu per square foot per year reduction could be achieved with an ASHRAE 90.1-2010-compliant building.
This new standard will provide substantial progress toward these reduction targets when promptly adopted and effectively enforced. However, the proposed standard language does not adequately address energy-efficient improvements to existing buildings.