Energy rating system for climate conscious operation of multi-unit residential buildings

Residential sector accounts for 17% of domestic energy use and 14% of the greenhouse gas emissions in Canada. Improving the energy performance of the Canadian residential building stock is vital in achieving climate action goals. A comprehensive review of popular building energy rating systems noted their lack of life cycle thinking. The scope of the popular rating systems is limited to operational performance, ignoring the condition of the assets. This paper proposes a condition assessment framework for the energy system of existing multi-unit residential buildings (MURB), which combines the concepts of asset rating and operational rating. Indicators were identified to define energy, environmental, economic, and asset performance of MURB. A life cycle assessment was conducted to quantify the overall environmental impacts of energy technologies from point of generation. A fuzzy logic-based approach was used to overcome the challenges due to data uncertainty and impreciseness. A case study was conducted for a residential building at UBC Okanagan, Canada. The weights at indicator level and category level were defined based on stakeholder consultation, while also considering different decision scenarios. A fuzzy rule-based approach was used to combine the different performance categories to obtain an overall condition rating. The results indicate that the performance of the case study building can be rated as “good” under operational, asset, and overall categories. The findings of this research can be used to improve the asset and operational management strategies in existing buildings and can inform the key stakeholders during the operational phase of the buildings.