Building energy retrofits in Canada under government fiscal constraints

Residential building energy retrofits can significantly reduce greenhouse gas (GHG) emissions and household energy costs when supported by effective fiscal policies. This study develops an integrated simulation–optimization framework to identify optimal retrofit strategies and fiscal parameters across ten Canadian cities. Results indicate that photovoltaic (PV) systems are favored in regions with high grid emission intensity or electricity prices, while thermal insulation levels remain near code minimums and improved air tightness is consistently preferred. Thermal energy storage and heat pumps are effective across most climates. Over a 20-year horizon, these strategies yield up to $7,000 in annual homeowner cost savings and over 100 tonne CO$$_{2}$$e of emissions reductions per building. Financial incentives including rebates ($23,000–$42,000), low-interest loans ($1,600–$8,000), and moderate energy taxes (0.4–8.8%) are essential to ensure affordability and adoption.