Accelerating the 1.5°C energy transition for Canadian residential buildings through selective direct electrification with heat pumps

Abstract

Limiting global warming to 1.5–2.0°C in line with our climate commitments will require decarbonization of residential buildings. The traditional approach starts with major energy efficiency upgrades to the building envelope followed by switching to low-carbon fuel sources for space and water heating. Building envelope retrofits have been a policy goal for over two decades in Canada and elsewhere, yet historical rates and associated emission reductions fall far short of what is required if we are to meet our climate targets. Alternatively, we propose direct fuel switching to electric heat pumps for space and water heating in regions with low-carbon electricity. Using a database of 44,463 home energy profiles in Waterloo Region, Canada, we modeled the energy efficiency and greenhouse gas emission impacts of building envelope retrofits and direct electrification. While all retrofit plans achieved significant energy efficiency gains (17-40%), so did direct electrification (70%) and building envelope retrofits plus electrification combined (70-80%). Only plans that included electric heat pumps achieved greenhouse gas emission reductions of 90% or more. Compared to the conventional approach, direct electrification with heat pumps may be a simpler, more effective, and more realistic approach for policies aiming to decarbonize the residential sector.