By Tyler Simpson
The ecoEII Net Zero Energy Housing Demonstration Project with the National Research Council of Canada (NRC) gathered five production home builders from across Canada to build net-zero energy (NZE) market-ready homes with off-the-shelf technology. At the conclusion of the project, the builders constructed 11 NZE dwellings: one four-unit NZE row house, one NZE multi-unit residential building (MURB) comprising six units, and five net-zero energy ready (NZER) houses. The houses constructed represented an important step toward the broader adoption of low operational carbon houses and provided critical insight into how these homes could be constructed in a cost-effective manner.
The recipe for a NZER or NZE house includes a building enclosure that incorporates optimized levels of insulation to limit thermal bridging, achieves exceptional levels of airtightness, engages fenestrations with a low U-value, and implements high-efficiency mechanical equipment. With this recipe in mind, and the support of a builder, the author’s NZER house, which was constructed in 2014, featured the following attributes as noted in Table 1.
With the parameters noted in Table 1, an energy model was developed in an energy simulation modelling software to approximate the house’s annual energy consumption, which revealed a utilization of 61 gigajoule (GJ) (Figure 1). If this house were built to the minimum requirements of the Supplementary Standards SB-12, amended in July 2016, from the Ontario Building Code (OBC), it would consume an additional 36 GJ of energy per year; which would mean less insulation, higher air leakage rate, and less efficient mechanical systems.
