The BC Energy Step Code is currently being implemented in British Columbia as an answer to future energy considerations in new building construction. It achieves this claim of moving towards “Net Zero” building construction by utilizing a building envelope first approach with modeling and a performance test.
The idea is that by raising a building’s theoretical energy efficiency a building will become a net zero home. In the process, there is a requirement for a certified and licensed energy adviser to be involved in the modeling, construction and testing phases of the building. (1)
In conjunction with this approach is the claim that builders can construct these buildings being “fuel-neutral”. Using this rationale the roles of mechanical systems design, testing and commissioning are omitted in the performance considerations of the building.
However, a net-zero building must include the omitted systems as the design and operation of necessary systems. These may include the ventilation and exhaust systems, water heating, laundry, and heating systems. Also, rain-water collection for irrigation and gray water systems or other load reduction schemes may all may contribute to the energy consumption and success of a “net zero” building.
Some of these services will always be required in a municipal setting such as electrical, water and waste. Reduction strategies are advised as further increases in population will add additional loads at existing consumption rates which might overload existing supply and waste systems infrastructure such as pipes and cable.
The final answer to how a building performs will be in the overall utility bills paid by the building for its operation. This includes the electrical power, gas consumption, solid and liquid waste disposal and water supplied. Unless you live in a remote rural area where none of these services are provided by a municipality, there will always be a design component of the mechanical systems that contributes to the operation of an energy efficient home.