A Summary of Recommendations from the Stretch Code Implementation Working Group
Overview
In recent years, municipalities across BC have taken to implementing additional energy efficiency requirements for new buildings beyond what is mandated in the BC Building Code (BCBC). In an effort to meet their own climate targets, cities like Vancouver have turned to zoning bylaws as a way to force developers to build to varying green building standards, from LEED to EnerGuide. While the intention is good, the result has been a complex and confusing set of requirements that can vary greatly from one municipality to the next. To address this issue, the BC government has convened the Stretch Code Implementation Working Group, a multi-stakeholder group tasked with developing a consistent framework for local governments – the ‘Energy Step Code’. The introduction of the Step Code is also the first of several measures for reducing the carbon intensity in new buildings alluded to in BC’s Climate Leadership Plan. The use of Step Code by local governments is voluntary, and uptake is expected to be higher in jurisdictions that are already leading in environmental design, such as Vancouver. It should be seen by developers, builders and other industry as a signal of how the BCBC is likely to evolve in subsequent years.
From the full report, the Step Code will:
- Lead to an actual reduction of energy demand in buildings.
- Focus first on building envelope design and second on equipment and systems.
- Provide flexibility to meet the changing needs and abilities of local governments.
- Deliver measurable feedback on building and program performance.
- Be compatible with local low-carbon and renewable energy systems.
- Provide capacity for local governments to pursue a long-term vision for the future of the energy efficiency of buildings and related climate action initiatives.
- Align key stakeholders.
Metrics The Step Code is a set of four incremental performance targets for new buildings that go from the existing BC Building Code to Net Zero Energy ready (NZER) buildings (NZER buildings are specifically designed to have the capacity to generate the energy they require to operate on-site). Performance is measured in terms of the efficiency of the building envelope (insulation, air leakage, doors and windows, etc.) and the efficiency of systems and equipment inside the building (heating, ventilation, etc.). While the Step Code is not tied to a specific green building standard or software, compliance does require the use of an energy modelling software and an air-tightness test. The first step, the “Enhanced Compliance Step”, is simply the minimum expectations of the BCBC, verified using the Step Code metrics. For consistency, each step is measured using the same performance metrics:
| Performance Measure | Metric | Description | Application |
|---|---|---|---|
| Total Energy Use Intensity | kWh/m2/yr | Most energy consumed in building in a year. Includes plug, process & lighting loads, HVAC | Part 3 |
| Mechanical Energy Us Intensity (MEUI) | kWh/m2/yr | Energy used by HVAC & DHW in a year. Does not include lighting, plug loads or consumer appliances | Part 9 |
| Percentage-Better-Than ERS Reference House3 | % | Uses energy modelling software to compare building performance to same building built to minimum BCBC | Part 9 |
| Thermal Energy Demand Intensity (TED) | kWh/m2/yr | Measures building envelope performance (used in Passive House) | Part 3 & Part 9 |
| Peak Thermal Load (PTL) | kWh/GJ | Energy required to heat/cool building on the coldest/hottest day of the year (sometimes called Design Heat Loss) | Part 9 |
Preliminary targets for Part 3 & Part 9 buildings are listed below. Targets are specific to climate zones; Climate Zone 4 applies in Victoria & Vancouver.
Table 1. Step structure and targets for Part 3: Climate Zone 4
| Step Level | Energy Modelling + Airtightness Testing | Equipment and Systems – Total Energy Use Intensity (kWh/m2/year) | Envelope – Thermal Energy Demand Intensity (kWh/m2/year) |
|---|---|---|---|
| Residential Buildings | |||
| Step 1 Enhanced Compliance (BC Building Code Performance) | Required | N/A | N/A |
| Step 2 | Required | 130 | 45 |
| Step 3 | Required | 120 | 30 |
| Step 4 | Required | 100 | 15 |
| Commercial Buildings | |||
| Step 1 Enhanced Compliance (BC Building Code Performance) | Required | N/A | N/A |
| Step 2 | Required | 150 | 30 |
| Step 3 | Required | 120 | 20 |
Table 2. Step structure and targets for Part 9: Climate Zone 4
| Step Level | Energy Modelling | Airtightness | Equipment & Systems | Envelope |
|---|---|---|---|---|
| Step 1 Enhanced Compliance (BC Building Code Performance) | Required | 3.5 ACH50 | BCBC using 9.36.5. OR ERS v15 ref. house (MEUI of 80 kWh/m2/year is likely, but not required) | Report on TEDI and PTL (TEDI 50 kWh/m2/year is likely, but not required) |
| Step 2 10% Beyond Code | Required | 3.0 ACH50 | 10% or better than ERS v15 ref. house OR MEUI – 60 kWh/m2/year | TEDI – 45 kWh/m2/year OR PTL – 35 Wm2 |
| Step 3 20% beyond Code | Required | 2.5 ACH50 | 20% or better than ERS v15 ref. house OR MEUI – 45 kWh/m2/year | TEDI – 40 kWh/m2/year OR PTL – 30 Wm2 |
| Step 4 40% Beyond Code | Required | 1.5 ACH50 | 40% or better than ERS v15 ref. house OR MEUI – 35 kWh/m2/year | TEDI – 25 kWh/m2/year OR PTL – 25 Wm2 |
| Step 5 50%+ Beyond Code | Required | 1.0 ACH50 | MEUI – 25 kWh/m2/year (no ERS option) | TEDI – 15 kWh/m2/year OR PTL – 10 Wm2 |
According to the summary on the BC government’s website, the Step Code will also be ‘fuel neutral’;
“The proposed Step Code also supports consumer choice, by allowing designers and builders to use natural gas, electricity, or other energy sources for their project without imposing a penalty on this decision. This ‘fuel neutral’ approach provides builders with the flexibility to make energy-efficient buildings using all available technologies.”
This means that the Step Code will not account for the potential benefits of renewable or low-carbon energy sources, which should be taken into consideration by local governments on a case by case basis.
The Building and Safety Standards Branch will focus next on developing the technical requirements of the Step Code, that will be enacted by regulation in the coming months. Full implementation is expected to take three to five years, and will involve the development of an Implementation Guide for local governments.
