Building enclosure retrofits for multi-unit residential buildings can result in significant energy savings when energy is a priority. Studies suggest up to a 90% reduction in space heating energy consumption could be achieved through a high performance building enclosure. However, such savings have not yet been confirmed through field measurement and verification. A high performance building enclosure retrofit was undertaken at a 13-storey multi-unit residential building in Vancouver, BC. The work was undertaken primarily as a renewals project, with energy conservation measures incorporated to also reduce energy consumption. The retrofit includes high performance windows (triple glazing, fibreglass frames), exterior wall insulation with low conductivity cladding attachment, and air sealing. Modeled energy savings predicted a 19% reduction in overall energy consumption, or a 68% reduction of in-suite space heating energy, realized through this retrofit. Whole building air leakage testing was performed before and after the retrofit to measure airtightness savings. Metered energy consumption was analyzed to determine the actual energy savings resulting from the enclosure retrofit through measurement and verification (M&V).
This paper will detail the high performance enclosure retrofit undertaken at the case study building. M&V results are presented to show the actual energy savings resulting from the retrofit. Modeled savings are also compared to measured savings to assess the accuracy of the modeled predictions. Airtightness testing results are presented to show the airtightness improvements achievable through an enclosure retrofit, as well as the associated energy savings. Actual project capital costs and annual savings from the energy conservation measures are presented to show the payback period and financial viability of a high performance enclosure retrofit. The findings and lessons learned from this project will assist in planning for future high performance building enclosure retrofits to lower the energy consumption of the existing building stock.
This paper was presented at the 2014 Canadian Conference on Building Science and Technology