Well Beyond Energy Codes: The Green Points Program in Boulder, Colorado

摘要

This paper documents energy savings and environmental impacts of the unique "Green Points" Program in Boulder, Colorado. Under the program, new dwelling units outperform by an average of 30 percent those that merely meet International Energy Conservation Codes (IECC). Beyond the requirement to meet IECC 2000 energy codes, new homes, additions and remodels over 500 square feet are required to incorporate measures associated with a minimum number of 'Green Points'. Green Points are awarded when measures are beyond-code improvements in insulation, windows, and the Heating Ventilation and Air Conditioning (HVAC) system by using REScheck? energy code software. Other measures include: using recycled-content materials; simplicity of design to minimize land use; water conservation and xeriscape landscaping; energyefficient plumbing (e.g., demand water heaters; devices for saving hot water); hard-wired Compact Fluorescent Lighting (CFL) lighting; energy-efficient appliances; natural cooling measures; auxiliary HVAC measures (e.g., heat recovery ventilation, hydronic heating, radiant slab, whole house fan); and solar (hot water, both active and passive space heating, and photovoltaic). The number of Green Points required is a direct function of the size of the structure, so larger homes must be particularly energy efficient and environmentally responsible to receive a building permit. In evaluating the consequences of the Program, the authors developed a hybrid methodology for quantifying the range of benefits flowing from the number of Green Points indicated on the builders' permit applications, while accounting for interactions between measures to avoid overstating savings. The results were integrated into an Access? database that calculates and displays aggregate energy and environmental savings as well as information disaggregated by measure for all dwelling units built, added to, or retrofitted under Boulder's Green Points Program. The resulting information is expressed in various graphic and tabular forms so that citizens, homeowners, builders, planners, and policy makers may understand the Program's effects. The average dwelling unit built under Boulder's Green Points Program has 1,695 square feet of floor space and saves 1,218 kWh of electricity, 298 therms of gas and 11,562 gallons of water with respect to a "just meets IECC 2000 code" dwelling of the same size. It is hoped that other communities would emulate the best features of Boulder's pioneering efforts and share practical wisdom about tactics that prove to be particularly effective in achieving energy-efficient homes that also conserve water and building resources.