www.rcabc.org  l  17 FEATURE performed less efficiently than expected. The Step Code changes all that. The Step Code uses measurable outcomes, or performance metrics, for specific buildings systems so that the building as a whole performs optimally. How a designer and builder achieve those metrics is theirs to decide. The metrics cover three critical building systems: •  The envelope – air tightness, measured in air changes per hour, or ACH, at a standard air pressure of 50 pa. •  Thermal energy demands – a measure of how thermally efficient the building is, to keep it at a standard, comfortable temperature. These metrics also take into account how much energy the building absorbs, even from the people who occupy it. •  Energy use – a measure of how efficiently systems inside the building function. This includes heating and cooling systems, together with electrical demands for appliances, lighting and other equipment. Energy modelling software and on-site testing are the keys to optimizing these three variables, to ensure the building works the way it should. Modelling for Part 9 buildings is undertaken by energy advisors who use sophisticated software to predict losses or gains based on manipu- lated variables within the model; engi- neering consultants, or “energy modellers,” typically assist with Part 3 building design. Testing is conducted on the building enve- lope specifically, to ensure that the whole structure complies with the benchmarks for air leakage established for each step in the Step Code. The Step Code sets out a series of energy-efficiency targets, or steps, that incrementally increase performance metrics over the course of 12 years, from 2020 to 2032. Each step parallels a recog- nized energy standard, like R-2000™ or Net Zero Ready Home™. The intervals between each of these targets, or steps, is left for each municipality to establish. By 2032, Step Code-compliant buildings will be 80 per cent more efficient than build- ings are today. The goal, of course, is more energy- efficient construction, both for Part 3 and for Part 9 buildings. Those efficiencies are necessary because, by 2032, the B.C. government requires new buildings to be “net-zero energy ready”; buildings must be designed and constructed to be capable of incorporating renewable energy technolo- gies that generate as much clean energy as they need to operate2 . Trust but verify Generally speaking, the Step Code means every new building will have to be modelled for energy efficiency, and then built to the design that optimizes building performance based on a compromise among the three critical building systems. Local building inspectors will require documentation about the design to show that it meets Step Code requirements. But the proof is in the the pudding, as the old saying goes. Testing verifies that the design actually works, at least from the stand- point of air leakage control. There are numerous ways to test the building for air tightness, but the best approach tests the building as a whole. Naturally, this gets complicated with larger and more complex buildings. Fortunately, trained specialists with the right equipment get paid to figure it out. Normally, every opening in the building 2  Renewable energy production is not currently a requirement of the Step Code.