Estimates of long-run energy savings and realization rates from a large energy efficiency retrofit program

Over 50 countries representing three quarters of global CO2 emissions have pledged to achieve a net-zero carbon economy by 2050, and energy efficiency improvements are a primary contributor in policy scenarios that attain this goal. However, uncertainties remain about the realized effectiveness of energy efficiency programs. This paper provides evidence on the realized savings from Canada's largest residential energy retrofit program. We use utility data from all single-family homes in a mid-sized Canadian city and detailed energy audit records from the EnerGuide for Homes database, which includes modeled predictions of energy savings from retrofit adoptions. The retrofit program reduces natural gas consumption in the average participating home by about 21%, representing 60% of predicted natural gas savings. Whole-envelope retrofits are predicted to reduce natural gas consumption by 67%, but in practice only half of these savings are realized. This underscores the importance of developing new modeling approaches that incorporate house-level data, which reflect the outcome of realized rather than predicted occupant behavior, to increase retrofit energy savings and return per subsidy dollar spent.