Home Performance with ENERGY STAR: Utility Bill Analysis on Homes Participating in Austin Energy's Program

Austin Energy, in Texas, is one of Home Performance with ENERGY STAR’s (HPwES’s) local sponsors and offers homeowners in their service territory complete home energy assessment and a list of recommendations for efficiency improvements, along with cost estimates. The homeowner can choose to implement only one or the complete set of energy conservation measures. The utility facilitates the process by providing economic incentives to the homeowner through its HPwES Loan program and its HPwES Rebate program. In 2005, the total number of participants in both programs was approximately 1,400. To determine the benefits of their HPwES program a statistical analysis was conducted using energy consumption data of HPwES homes provided by the utility. This report provides preliminary estimates of average cooling savings per home from the HPwES Loan Program for the period 1998 through 2006, and the estimates are based on electricity billing records provided by the utility for more than 7,000 households. This study provided a statistically rigorous approach to incorporating the variability of expected savings across the households in the sample together with the uncertainty inherent in the regression models used to estimate those savings. The results from this preliminary analysis suggest that the utility’s HPwES program had a significant impact on reducing average cooling electricity for participating households. Overall, average savings were in the range of 25%-35%, and appear to be robust under various criteria for the number of households included in the analysis.