Energy Efficient Retrofit of a High-Rise Multifamily Building

The National Institute of Building Sciences estimates that over 70% of the buildings that will be present in 2030 already exist today. The sustainable and energy efficient renewal of existing buildings is paramount to reducing our environmental footprint and improving the operational affordability of buildings. Buildings constantly go through renewals as components including windows, cladding, roofing, and mechanical equipment reach the end of their service lives. Rather than choosing standard or condominium replacement components, high performance components and designs can reduce energy consumption at low incremental cost.

This paper presents a case study of an energy efficient building enclosure retrofit of a 13 story multifamily building in Vancouver, BC. Renewal work to the building enclosure included the addition of continuous exterior insulation with low conductivity cladding attachment, replacing the existing windows with triple-glazed fiberglass frame units, and air sealing. The overall effective R-value of the building enclosure (walls, windows and roof) was improved from R-2.8 hr-ft²-F/Btu to R-9.1 hr-ft²-F/Btu. Pre- and post-retrofit whole building airtightness testing showed a 55% reduction in air leakage. Whole building energy modeling was performed to assess potential retrofit measures, to estimate energy savings and to complete a cost-payback analysis. Measurement and Verification (M&V) was performed following one year of post-retrofit operations. The retrofit resulted in a measured 19% overall energy savings, reducing in-suite electric baseboard space heating energy by an estimated 63%.

This paper was presented at the 2015 BEST4 Conference.