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BC Step Code - Shoreline

Feb 23

Understanding The BC Step Code

Are you wondering how the new changes to energy efficiency requirements will affect you? Worry no more - Shoreline Building Performance can guide you through this transition with ease!

What is the BC Energy Step Code? In 2017, the BC Energy Step Code is a performance-based strategy for meeting energy efficiency requirements for buildings. It presents a gradual pathway to achieve Net Zero Energy Ready buildings for all new constructions by 2032. While the lower steps have been voluntary in many districts and municipalities, the next code cycle, expected to be released in mid-December 2022, will designate Step 3 of the BC Energy Step Code as the recommended compliance path going forward. Although a prescriptive backstop has been included in draft versions of the building code update to allow compliance in areas without access to an energy advisor, much stricter minimum values must be met to comply with this approach. The performance-based approach has been identified as more cost-effective in markets with access to an Energy Advisor.


Since the incorporation of energy efficiency requirements in the BC Building Code in 2008, designers, architects, and builders have had the choice of complying with the prescriptive levels of individual building components or utilizing a performance-based approach by a combination of pre-construction energy modelling and on-site testing. Historically, most builders in British Columbia have chosen to follow the prescriptive route since it did not require the involvement of outside consultants to complete energy modelling. As the operational energy consumption associated with buildings gains more attention, builders require additional flexibility offered by a performance-based approach to meet the new energy efficiency requirements. By using energy modelling to assess the overall performance of the house through various metrics related to the building envelope and mechanical systems, energy advisors can provide the guidance required to construct the high-performance homes of the future. Through this collaboration, home builders can optimize the building envelope and mechanical systems on their projects and pinpoint where the greatest benefits can be realized. Step 3 will demand that buildings be 20% more efficient than the National Building Code reference house, verified through a range of metrics and on-site testing, which will be further explained below.

To read more about The BC Step Code, click here. 

Let's take a closer look at the metrics used in the BC Energy Step Code to measure the energy efficiency of Part 9 and Part 3 buildings, which can be broken down into three categories: airtightness, equipment and systems, and the building enclosure.


Firstly, airtightness measures the amount of uncontrolled leakage between the interior of the home and the exterior environment, and is measured in air changes per hour (ACH). To achieve Step 3 compliance, builders must achieve an airtightness value of 2.5 ACH for single-family detached homes, which can be measured using a blower door to pressurize or depressurize the building to a pressure, typically 50 pascals (Pa) in a residential application. Working with an energy advisor to conduct a pre-drywall blower door testing and blower door directed air sealing can be a valuable exercise in learning the common leakage points, as well as diagnosing and correcting any major deficiencies early in the project to ensure targets are met. An as-built blower door test is required once the home is complete, and the final values will be input into the as-built energy model. While the airtightness targets in the code do not explicitly aim to improve indoor air quality, an airtight home with proper ventilation contributes to good occupant health.


Moving on to equipment and systems, the choice of high-efficiency systems for space heating and cooling, followed by hot water heating, can have a significant impact on a home's energy rating. Step 3 requires equipment and systems to use 20% less energy than the reference house to comply with the percentage better than reference house metric, or meet the mechanical energy usage intensity (MEUI) target, an intensity metric based on building energy use per square metre of floor area.


Lastly, the building enclosure metrics assess the enclosure performance as a percentage better than the reference house or through thermal energy demand intensity (TEDI), which considers the heat loss and gain through the exterior envelope, uncontrolled air leakage, solar heat gains, and internal heat gains from occupants, heat recovery of ventilation air, and internal gains associated with space and water heating equipment. TEDI is expressed as energy required per square metre of floor area, and an adjusted TEDI metric may be used to comply in colder climates. All mechanical equipment and systems are set to match the reference house in the energy model to isolate the enclosure performance and remove any gains or losses associated with equipment and systems.


If you're wondering how to ensure compliance with the BC Energy Step Code on your next project, working with a team of experienced Registered Energy Advisors can provide you with invaluable support. At Shoreline Building Performance, our Advisors work closely with builders to offer cost-effective solutions with a focus on constructability, drawing from their extensive field experience.


Engaging an energy advisor can commence at the design stage for complex projects, but usually begins by evaluating a set of pre-permit drawings to create an energy model based on the proposed plans and mechanical equipment and systems, ensuring compliance with the proposed step. The builder is required to submit a copy of the pre-construction compliance report with the permit application to the authority having jurisdiction. Assuming no revisions are needed, Shoreline Building Performance guarantees a 72-hour turnaround on pre-construction compliance reports from the time of confirming the project.


While a mid-construction blower door test is not required, it is often recommended to identify significant deficiencies before installing drywall, providing confidence that the structure will meet the air tightness requirement during the as-built site testing.


The final step in the process involves a site visit to verify that the final structure matches the proposed plans, with any modifications accounted for in the energy model to ensure compliance. At this stage, the final blower door test results are also recorded and entered into the energy model. The energy model is then updated, and an as-built compliance report and Energuide label are issued for the home.


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