A study to optimize the potential impact of residential building energy audits

The Colorado College Energy Audit and Retrofit Program is a non-profit organization that teaches students the science and mechanics involved in energy audits and retrofit work through service–learning and community-based research projects. This approach represents a “win–win” scenario where the college contributes to maximize learning and minimize costs to the community. The method of identifying homes for energy audits has evolved from responding to homeowner requests to a proactive approach aimed at targeting older low-income neighborhoods and working with existing neighborhood associations. Recent work on the Mill Street Neighborhood in Colorado Springs, Colorado is presented in which a sample of homes (N = 14) received thermal audits, complete with blower door tests and Energy-10 computer modeling. The results are tabulated, analyzed, and extrapolated over the entire 145 homes in the neighborhood. The normally distributed ACHn values and the skewed distributions of Raver values and building sizes are discussed. A method of identifying unusual occupant behavior, relative to the building quality, is presented where the Home Heating Index is compared to a Building Thermal Performance Index (Raver/ACHn). Estimates from extrapolation of the data predict that an investment of $146,500 USD in retrofit materials will yield a total annual neighborhood savings in energy, utility costs and GHG emissions of 9.1 × 106 kBtu (9.6 × 109 kJ), $64,000 USD and 555 US tons (5.0 × 105 kg), respectively, providing a simple payback time of 2.3 years. This efficient method of neighborhood energy audits provides data that could support neighborhood renewal grant proposals to purchase materials for follow-up retrofits and supports municipal demand-side management programs.