Retrofitting homes in Ontario entails significant embodied emissions: new policies needed

Emissions reduction policies and programs should consider both the operational emissions reduction from single family home retrofits and the embodied emissions of the retrofit materials. This is because it can take 0.9–10.1 years before the emissions savings from building envelope upgrades in a gas-heated home equal the embodied emissions from the materials used. The wide range reflects the range of embodied emissions for different insulation and window replacement options. Heat pumps also have significant embodied emissions from their manufacture and from refrigerant leaks, but it takes less than two and a half years of operations in Ontario to offset the emissions investment relative to heating with a gas furnace. We recommend that Canada accelerate the phase out of insulation materials with high embodied emissions and increase incentives for window replacements. Programs and policies should also consider the age of the home and the potential energy savings when recommending building envelope improvements to maximize the total emission reduction potential. Finally, heat pumps should be promoted in all homes where low carbon electricity is available because this is the simplest and most effective way to reduce carbon emissions, especially when embodied emissions are considered.Key policy insights The embodied emissions from retrofits of single-family homes can be significant and should be considered in retrofit policy design.Canada and other countries should accelerate the phase out of high embodied emissions insulation materials.To maximize energy efficiency gains and minimize retrofit embodied emissions paybacks, building envelope upgrades should focus on older homes.Heat pumps remain a good climate investment in Ontario because the emissions from heat pump refrigerant leaks are offset by less than two and half years of operational emissions savings.