A study was undertaken to understand the total energy and space-heating energy consumption of mid- and high-rise multi-unit residential buildings (MURBs) in the Lower Mainland of British Columbia. To perform this study, detailed monthly energy consumption data was provided by the local gas and electric utility providers for over sixty MURBs constructed during the past 40 years. Detailed information including drawings, mechanical system specifications, and building history were collected for each building to understand the influence of different characteristics of a building on its overall energy performance. This initial selection of buildings was then narrowed to buildings that had previously undergone building enclosure rehabilitations to address moisture damage. These buildings provided the opportunity to directly compare pre- and post- building enclosure rehabilitation energy consumption and analyze potential energy savings from more thermally efficient and airtight building enclosures. Whole building energy models of these buildings were created using detailed as-built enclosure R-values, airtightness values from research and some field testing, mechanical information, and building operating conditions. Metered energy was then compared to simulated predictions and calibrations were performed to improve the accuracy of the models to better predict the actual energy consumption. Because information was available for both pre- and post-rehabilitation cases, it was possible to assess the ability of a pre-rehabilitation building model to predict the energy consumption of a corresponding post-rehabilitation model. Additionally, common assumptions regarding high-rise residential building energy use were tested including the level of detail required to accurately simulate the thermal performance of a building enclosure. Using the knowledge gained through this energy simulation process, recommendations can be made to improve the accuracy of representative energy use patterns for retrofits and new construction of high-rise multi-unit residential buildings.
This paper was presented at the 2011 Canadian Conference on Building Science and Technology.