Evaluation of a Wisconsin Utility Home Energy Audit Program

In February 1978, the Wisconsin Power and Light Company (WPL) offered its residential gas-space-heating customers free on-site energy audits. Between then and June 1980, they audited about 19,000 homes. In September 1979, WPL decided to evaluate their audit program. The data they assembled included natural gas consumption records, the need for specific weatherization measures (as determined during their energy audits), and customer reports of their demographic characteristics and recent energy conservation practices and measures. This information was available for samples of customers that had received an audit in 1978 and for samples of customers that had not participated in the WPL program. Comparison of the data across the two groups showed considerable similarity. Program participants and nonparticipants were much alike in terms of pre-audit gas consumption, demographic characteristics, adoption of conservation practices, and attitudes on energy issues. The two groups differed significantly only with respect to conservation measures; this difference was probably due, in part, to the 1978 audits. These findings are somewhat weakened by the low response rate to the mail survey among nonparticipants. Regression equations were developed to explain natural gas use for the two heating seasons after the 1978 audit The results showed the importance of floor area, age of house, household income, number of occupants, and temperature setting on gas use. The equations also showed that the 1978 audits had a statistically significant effect on annual gas use. Households that had an audit in 1978 reduced their consumption by 8 MBtu/year (8%) because of the audit. However, a regression equation estimated for the heating season before the audit showed that the audit group consumed 7 MBtu less than did the nonaudit group, which suggests that the audit only saved about 1 MBtu/year. ♦Research sponsored by the Office of Conservation and Renewable Energy, U.S. Department of Energy, under contract W-7405-eng-26 with Union Carbide Corporation.