Evaluating summertime overheating in multi-unit residential buildings using surveys and in-suite monitoring

Abstract

Multi-unit residential buildings (MURBs) are an important source of housing in many urban regions including Toronto, Canada, where MURBs provide over half of the city’s housing. Many of these MURBs were constructed following the second world war (Touchie et al. 2013) and are in need of renewal to address energy performance and indoor environmental quality (IEQ) concerns. The Toronto Atmospheric Fund (TAF), a nonprofit corporation whose mandate is to reduce greenhouse gas emissions in the City of Toronto, and a local social housing provider have partnered to improve the performance of seven post-war MURBs through retrofits. To help prioritize retrofit options and assess IEQ, a monitoring program including pre-retrofit resident surveys and in-suite monitoring was implemented. The resident surveys included questions about basic demographics, resident behavior, and perceptions about IEQ. To supplement the surveys, temperature, relative humidity, and mean radiant temperature were monitored for one year in 65 suites. This paper examines the findings from both the in-suite monitoring and the resident surveys to determine the IEQ issues that should be addressed during the retrofit process. The analysis presented focuses on the summertime condition, which is of particular concern given the vulnerable populations housed in these buildings and the lack of central cooling facilities. The findings suggest that an air temperature threshold may be insufficient to ensure thermal comfort given the range of survey responses associated with the observed suite temperatures. Based on the data collected, it was not possible to explain the differences between the survey responses related to thermal comfort and the monitored conditions. Factors such as air speed, exposure to solar gains, and resident perceptions may contribute to these differences. The paper concludes with a discussion of some insights from the comparison between the survey and monitoring data and how they best can be used to inform the design of future retrofits and monitoring programs.