A Performance-Driven, Multi-Dimensional Framework for Assessing Environmental and Functional Quality in Buildings

Abstract

Since modern humans spend over 90% of their time indoors, the majority of this time at home, understanding how residential buildings impact the environment and the building occupants is imperative in improving future design and retrofit strategies. Multi-unit residential buildings in particular represent a growing portion of Canada’s building stock and present unique challenges related to building quality. With 40% of global energy consumption represented by buildings, optimizing their design in specific typologies can reduce overall environmental impact and, in many cases, improve thermal comfort of residents. Likewise, daylight in buildings has been shown to impact occupant well-being and may also contribute to energy efficiency. One final aspect affecting indoor environmental quality that is important to occupant health is indoor air quality, which has gained increased focus with recent wildfire smoke events.

This study aims to quantify the environmental quality of existing multi-unit residential buildings in the Waterloo Region through three main research objectives: 1) estimating energy performance through modelling current energy use and potential energy production; 2) developing a modelling methodology that allows for the comparison of daylight and energy performance at the unit level; and 3) measuring pollutant concentrations, temperature variations, and occupant perceptions in case study units. The three areas of focus are tied together through 93 survey results from 8 case study buildings covering resident perceptions of thermal comfort, daylight, and air quality.

For the first objective, case study buildings were modelled and validated using utility data, producing estimates of current energy use, energy use after retrofit measures are implemented, and potential photovoltaic energy production. Public housing case study buildings constructed in 1960-1980 were found to have the highest energy consumption, with lower perceived thermal comfort. Overheating was identified as a concern across both public and private housing from the oldest era of construction. To address the second objective, daylight models were created of four units representing each cardinal direction of the building façade and these results were compared to the unit-level energy modelling results. 37.5% and 44.6% of the units studied did not meet the daylighting thresholds for sDA and illuminance, respectively. Balcony width and unit aspect ratio were determined to have the greatest impact on EUI through a correlation analysis.

The third objective was achieved by conducting indoor air quality measurements in 8 units across 5 case study buildings and distributing a questionnaire to residents. Correlations were explored between concentrations of indoor and outdoor pollutants, temporal changes across units, and comparison with questionnaire results. Perceived indoor air quality was found to have little correlation with measured results of pollutants, highlighting the need for increased testing in units and education of building occupants. These objectives were validated using 93 survey results from 8 of the case study buildings, resulting in a cohesive analysis of various aspects of environmental quality. The new dataset of existing MURBs coupled with analyzing the impacts of energy use, daylighting, and indoor air quality on building performance allows for a better understanding of current conditions and improved design of future housing developments and retrofits.