Actual Versus Perceived Energy Savings: Results from a Low-Income Weatherization Program

John Gardner and Lisa A. Skumatz, Skumatz Economic Research Associates, Inc.

Keywords

Abstract

Energy efficiency program evaluation relies on estimates of energy savings in order to draw reasonable and credible conclusions about the relative benefits of the improvements that programs implement. Common sources of estimates of energy savings are deemed savings, measured savings or self-reported savings.

The authors decided to examine whether there were patterns in discrepancies between deemed and perceived savings that could be attributed to predictable factors, and identify whether (1) one measure can reasonably be used as a substitute for the other if one measure of savings is not available; and (2) whether these perceptions color the respondent’s opinion of the energy efficiency measures, the program, and potentially, the utility itself.

We used a combination of utility-estimated energy savings data and phone survey data collected from participants in a state-wide low-income weatherization program in an attempt to identify important causes of discrepancies between utility-estimated and self-reported savings estimates. Using a series of statistical models of reported savings differentials, we found that demographic factors are not effective predictors of savings discrepancies. However, explanatory factors with substantial explanatory power were found, including the presence of program benefits above and beyond the cost savings on energy (non-energy benefits). Additional statistical analyses demonstrated that perceptions of high savings were correlated with high program satisfaction. The results indicate that a simple relationship between perceived and actual savings and easily identified exogenous variables may not exist. However, the work indicates there does appear to be a relationship between perceived energy savings, non-energy benefits, and program satisfaction.