The impact of window-to-wall ratio on energy intensity of existing office buildings in Ontario and Quebec

Energy codes, such as SB-10, provide significant impact on the thermal performance of the building envelope. For design of new buildings, a window-to-wall ratio (WWR) of 40% is considered as a threshold in Ontario for using prescriptive solutions for thermal resistance of the enclosure. This study will demonstrate the relationship of the energy intensity of the existing office building to the WWR, through analysis of 15 office buildings located in Ontario and Quebec. Recent studies indicate that building geometry can influence the energy efficiency of the building; nevertheless, factors that impact energy intensity of existing buildings are not researched in full, and this study’s aim is to minimize the knowledge gap in this field of literature. The outcome of this research shows that WWR directly influences energy intensity of the building. Energy balance calculations and energy loads distribution showed that WWR impacts on average 15% of overall energy consumption