Comparison of actual energy savings with audit predictions for homes in the north central region of the U.S.A.

Abstract Utilities throughout the U.S. offer their customers on-site home energy audits. The main purpose of these audits is to give households specific suggestions on cost-effective conservation measures suitable for their home. Unfortunately, little is known about the accuracy of these audit procedures or on the actual energy savings achieved in these homes. Data from a recent evaluation of a home energy audit program in Minnesota were used to analyze the actual energy savings achieved in audited homes and the relationship between actual and predicted savings. The actual reduction in weather-adjusted natural gas use for 346 gas-heated single-family homes averaged 19 M Btu/year. The variation, however, was quite large: gas use increased in almost 20% of the homes, while gas use decreased by more than 50 M Btu/year in 10% of the homes. The median ratio of actual-to-predicted gas saving was 0.66, suggesting that, on average, two-thirds of the expected energy saving was actually realized. However, the actual saving was within 50% of the audit prediction in only 45% of the homes studied.