LAUSR

Abstract The residential sector has a major role to play in the transition to green energy. The heating and cooling of buildings represents 40% of global energy consumption, while vast energy savings potential remains largely unexploited. Given the low turnover of housing stock and ambitious emission reduction targets, most of this potential will require retrofitting existing buildings. In this study, we investigate how to best take advantage of retrofits in the residential sector of Quebec (Canada) using environmental and economic criteria. Within the province, heating is mainly powered by electricity from renewable sources. We propose an approach based on a consequential life cycle assessment that focuses on marginal impacts combined with “consequential life cycle costing.” Seven alternatives using different heating systems and building envelopes are compared to a reference case, which consists of a typical detached house heated with electric baseboards. This approach permits an assessment of cost-efficiency and sustainable technological solutions. Our results show that the amount of energy saved by retrofits (especially for air source heat pumps with and without building envelop improvements) generates environmental and economic benefits. Furthermore, if the saved electricity is exported to replace natural gas, then the local electricity savings is quite beneficial. These results provide key new insights on the energy policies affecting the building sector, especially for regions in cold climates such as Quebec.