Whole-life Carbon Analysis of Residential Buildings Retrofit Projects in Ontario

<p dir="ltr">Life cycle assessments (LCAs) of buildings provide a means to understanding the whole life carbon of the built environment, which can facilitate decision-making about efficient building systems and low carbon design approaches. This paper conducted LCAs on two existing social housing buildings undergoing retrofits. The two buildings were assessed in terms of operational and embodied carbon emissions in three scenarios, the existing building, a retrofit following the Ontario Building Code requirements, and a retrofit approach designed by TCHC. This research examined ways to balance embodied and operational energy consumption and assessed retrofit options to reduce the whole-life carbon of buildings. Energy Plus and One Click LCA software were used to conduct building simulations. The results suggest that while the TCHC retrofit has the lowest whole-life carbon emissions, the OBC design using an air source heat pump (ASHP) also significantly reduces emissions. The low emission factor of electricity in Ontario contributes to the OBC with ASHP's low carbon emissions compared to natural gas-powered systems. Therefore, electrification in Ontario’s context can be a viable pathway to reducing carbon emissions in the built environment. The paper also highlights the importance of electricity grid emissions reductions and how the energy factors of electricity can directly impact building whole-life carbon.</p>