The Shell Game: Finding Thermal Savings in Residential Retrofit Programs

A successful energy efficiency program reaches the intended audience, results in specific, direct actions to improve energy efficiency and estimates realistic energy savings from these actions. Many factors contribute to the success of a program, including program design, understanding of the target audience, accurate tools for estimating savings, and incentive levels. This paper covers three approaches to achieving thermal savings in existing homes that have been implemented in the Northeast USA and the savings resulting from these efforts as determined through independent impact evaluations. The limits on potential savings as a function of building stock age are also explored. Impact evaluation indicates that realized savings for all of the evaluated programs fall short of the programs’ reported savings. However, the gap between the program reported and evaluated savings varies greatly from one program to the next while the savings as a percent of pre-treatment use is relatively consistent. This result may be related to problems with program design, analysis tools and/or characteristics of the target population and funding levels. The paper covers the following topics:  Comparing and contrasting the key aspects of the program design  Discussion of various metrics for measuring savings  Presentation of results from independent impact evaluations  Analysis of the evaluation results in the context of the program designs  Exploration of the reasons that program-reported energy savings are not being achieved The final section will cover recommendations to provide guidance for evaluators and program staff working within the residential market.