The R-value ranges and assemblies shown in this guide as examples for reaching near net zero are based on a combination of energy modelling and industry experience. Energy modelling was conducted to establish potential design strategies to achieve the upper steps of the BC Energy Step Code (Steps 4 and 5) as well as net zero performance per the Canadian Home Builders' Association guidelines.

The successful design strategies were combined with industry experience to determine value-optimized enclosure performance. Beyond strictly construction cost, optimization for value was determined by also considering each assembly's effect on occupant comfort, overall constructibility, and end-user operation cost. The value-optimization also considered the climate zone the building is located in, which may necessitate wall and roof assemblies with higher minimum effective R-values due to colder conditions, regardless of potential trade-offs that may be available.

The following page shows an illustrated map of Canada with climate zones noted and potential effective R-value ranges for the roof, walls, and below grade assemblies that may be considered when designing to reach near net zero. The ranges given demonstrate the wide variation based on the optimization pathway used to reach near net zero (i.e., trade-offs with mechanical systems and other building elements).