Toronto’s ambitious goal to achieve net-zero emissions by 2040 has placed a renewed focus on the city’s building sector, which accounts for more than half of local greenhouse gas (GHG) emissions. Within this context, deep energy retrofits—especially for Toronto Community Housing’s aging low-rise stock—represent a crucial step forward. Among the most promising approaches is the Energiesprong methodology, a Dutch-born strategy that utilizes prefabricated panels to wrap buildings in high-performance envelopes with minimal disruption to residents. But how does this retrofit strategy perform when applied to solid masonry townhomes common in Toronto?
This white paper investigates the hygrothermal performance risks of Energiesprong-style retrofits using two types of insulated panels—cellulose-filled wood-framed panels and EPS-insulated structural insulated panels (SIPs)—on a pilot building in Etobicoke. The study introduces a new Hygrothermal Performance Sensitivity Analysis to test how factors like brick type, initial moisture content, and panel material influence the risk of moisture accumulation, mould growth, and wood decay after retrofit. The findings offer practical insight into how to scale deep retrofits while safeguarding building durability and occupant health.



