How can cities continue to expand and provide housing for a growing population, while limiting the negative impacts on the environment that may arise from such new construction?
Recent amendments to the Vancouver Building By-law (VBBL) are meant to address growing concerns with this complex issue and come in the form of three possible energy compliance requirement pathways for all new construction of residential buildings three storeys and under.
The changes to the VBBL are part of the implementation of the City of Vancouver’s Climate Emergency Action Plan, a goal of which is reducing carbon pollution in Vancouver by 50 per cent by 2030. Over half of the carbon pollution in Vancouver comes from burning fossil fuels in buildings – so the city has implemented these new energy requirements to ensure new builds are constructed in a more climate-friendly way.
The intention behind providing three pathways is to provide flexibility for each project, while still allowing Vancouver to meet its goals on climate change. Anyone considering the construction of one-to-three-storey residential buildings should be aware of these recent changes to the VBBL and must consider which of the three potential energy compliance pathways is most appropriate for their intended build: the prescriptive path, the performance path or the passive house path.
The prescriptive path
The prescriptive path focuses on each building component, which must meet or exceed the prescribed targets. Key components include the building envelope, mechanical appliances, glazed doors, skylights and heat pumps. One key aspect of the prescriptive path is that it does not allow for any gas-fired appliances for space or hot water heating.
This compliance pathway is the most straightforward as it sets out key metrics for each building component – if these metrics are met, the building is compliant. However, it can be inflexible because there are no opportunities for trade-offs. Even if one building component significantly exceeds an energy target, all the other components must still meet their individual targets and if even one component falls short, the building is not in compliance.
The performance path
The performance path also contains some prescriptive requirements for the performance of certain building components, but it incorporates more flexibility than the prescriptive path because it takes an overall look at the building’s energy use and emissions intensity to determine if targets are met, rather than focusing on each individual building component.
There are three key energy performance metrics which have associated targets set out in the VBBL: thermal energy demand intensity, mechanical energy use intensity and greenhouse gas intensity. A new build that follows the performance path must meet the requirements for each metric, but because it is more of an overall assessment than the prescriptive path, there can be more trade-offs (one of which is the allowance of gas-fired appliances). An important thing to note is that this path requires an energy model calculation by a licensed energy adviser, which may add to the cost to prepare a permit application.
The passive house path
The passive house path is the most ambitious option. The passive house standard is an international program that began in Europe aiming to create buildings with close to net-zero emissions. Similar to the performance path, the focus is on the overall performance metrics of the building rather than particular component requirements. The City of Vancouver describes the passive house program as the model for achieving all the targets set out in the city’s Climate Action Plan.
The downsides of the passive house path are that the requirements are more stringent than the performance path requirements, the availability of suitable building materials will be more limited and the certification process can be onerous and costly because it requires the involvement of a third-party passive house consultant. However, this pathway could be a viable option for those who want assurance that their building will meet potentially more onerous energy-related requirements in the future. Additionally, the city provides incentives for those choosing this path in the form of removing regulatory barriers and potentially granting zoning bylaw variances involving allowable floor area, building height/depth, yard setbacks and/or external design. •
Norm Streu is executive vice-president, NCM development, Nexii Building Solutions. Christopher Hirst is managing partner at Alexander Holburn LLP. This article was drafted with the assistance of Tenley Pearce, articled student.