Residential energy efficiency retrofits: How program design affects participation and outcomes

Better methods of characterizing and addressing heterogeneity in preferences and decision making are needed to stimulate reductions in household greenhouse gas emissions. Four residential energy efficiency programs were delivered consecutively in the Region of Waterloo, Canada, between 1999 and 2011, and each offered a unique combination of information, financial reward structure, and price. A natural quasi-experimental intervention design was employed to assess differences in outcomes across these program structures. Participation at the initial (evaluation by an energy advisor) and follow-up (verification of retrofit) stages, and the material characteristics (e.g., energy performance) were measured and compared between the groups of houses included in each program at each stage. The programs appealed to people with different types of material concerns; each phase of the program was associated with houses with a different mix of material characteristics and depths of recommended and achieved changes. While a performance-based reward attracted fewer houses at each stage than a larger list-based reward, older houses with poorer energy performance were included at each stage. The findings support experimentation with program designs to target sub-populations of housing stock; future program designs should experiment more carefully and with larger performance-based rewards and test parallels with potential carbon market structures.