The most effective GDS framework to reduce energy waste and emissions is the step and cap mechanism or tiered approach. Similar to the gold standard of GDS, the Toronto Green Standard, a tiered approach is based on a series of progressive green development measures. Each tier seeks a higher level of energy performance and emissions reductions. After a set period, the minimum mandatory requirement is updated, and the second tier now becomes the mandatory minimum.

The tiered approach seeks continuous improvements on energy reduction targets. It also encourages the voluntary uptake of higher tiered performance measures (Tier 3 and above) through various financial mechanisms or incentives. A tiered approach can be aligned with the tiers of the proposed 2020 model codes (see Table 1) will help to better prepare local markets for net-zero building codes tier advancements into the future.