Investigating a Deep Energy Retrofit Package for Nova Scotia's Affordable Housing Sector

The construction industry is a significant contributor of greenhouse gas emissions in developed countries around the world. The building sector has adopted new ideas and initiatives in recent years to help tackle climate change, but the move toward net zero has been gradual. This is particularly troublesome in countries with cold climates, like Canada, where fossil fuels are used extensively for space heating. This study investigated an optimal deep energy retrofit package for an affordable housing building owned by the Housing Trust of Nova Scotia to determine its constructibility, effectiveness, financial feasibility, as well as scalability and repeatability for buildings of similar archetype. This project was intended to act as a proof-of-concept to address much needed deep energy upgrades to Canada's existing building stock, with particular focus on affordable housing. The objective was to create an exterior deep energy retrofit package that ensures high performance, minimal disruption to occupants and fosters a "pride of place" for its residents. The results indicated a 95% reduction in space heating demand and projected thermal comfort improvement by including a cooling system. Upgrades to water use equipment for the entire building decreased the water system energy demand by 60% when compared to the baseline model. Similarly, the energy use intensity for the proposed retrofit shows a significant reduction from both the baseline and the ENERGY STAR benchmark for multifamily residential buildings, with an energy use intensity (EUI) of 62 kWh/m². Furthermore, the annual greenhouse gas emissions reduced from 57 kgCO₂/year to 2.47 kgCO₂/year, illustrating the significance that deep energy retrofits have on contributing to the achievement of federal and provincial GHG emission targets. Additionally, the methodology investigated in this research implies that buildings of the same archetype are easily repeatable and scalable. Some design details of the panels require consideration with buildings that have more complex geometry and building components, such as balconies. Overall, the deep energy retrofit package has a high likelihood of replication and application to similar buildings.