Some B.C. Builders are Reaching Step Code Specs Without Even Trying
Testing results reveal recently completed or under-construction homes in Kamloops and the Kootenays would meet the airtightness requirements of the Lower Steps today.
Though many homebuilders are expressing anxiety about having to soon meet the requirements of the BC Energy Step Code, a series of recent assessments suggest that a good number of them may already be doing so on key metrics without changing their construction practices.
The evidence is emerging from a Performance Path Training Program now underway under the supervision of the Canadian Home Builders’ Association Central Interior (CI), and also from assessments shared by an energy advisor working in the province’s East Kootenay region.
It started when Rose Choy, Canadian Home Builders’ Association Central Interior executive officer, had the idea to run a blower-door test on the 2018 Lottery Training House. Each year, the association partners with the apprenticeship program at Thompson Rivers University and the Kamloops YMCA/YWCA to build a demonstration house. Once complete, the Y raffles off the house as a fundraiser.
A Big Fan of Your Work
Energy advisors run a blower-door test on homes to determine its airtightness, a leading metric used in the BC Energy Step Code. (The BC Building Code has required homes to prevent air leakage for years, but the BC Energy Step Code requires testing to ensure that all homes are actually meeting the minimum requirement.)
The test measures how many times in one hour a given home’s total air volume will be exchanged through “leaks” in the envelope—cracks around windows and pipes and so on, when it is depressurized with a fan. Energy advisors can run the test twice: First, at the mid-construction stage, when the air barrier is on, and again when the house is completed.
“We had the idea, let’s test this house, and run the numbers through the Step Code,” said Choy of the 2018 Training House. “And when we did, we were so happy to learn that it was [meeting the requirements of] Step 2.”
Airtightness testing yields one of the three metrics that together determine a home’s compliance with a given step of the BC Energy Step Code. The Training House scored 1.7 air changes per hour which is a respectably low number. (It’s a much better result than the assumed BC Building Code minimum performance of about 2.5 air changes per hour.)
“We were very happy with that result,” reports Choy.
Model, Test, Score, Repeat
Choy then secured a grant from BC Hydro’s Residential New Construction program, to help her members get up to speed on the performance-based approach that is at the centre of the BC Energy Step Code, and get a sense of how well their homes perform using existing construction practices. FortisBC also contributed funds to the research project.
Work is now underway to model, test, and score 16 additional new homes in and around Kamloops, including next year’s lottery training home. It’s early days in the study, but preliminary results are encouraging.
Licensed energy advisor Nick Watson has been doing the Kamloops assessments. To date, he has done three finals and one mid-construction test. The mid-construction test came in at Step 2 on airtightness, and of the three finals, two met the overall requirements of Step 2 and one hit Step 3.
Watson usually works with builders who build higher-performance homes, such as those seeking BuiltGreen certification. The Kamloops project is his first time working with builders who are just building in the usual manner. (That said, since the homes in question are custom builds, some are already installing above-minimum energy-efficiency measures, such as heat-recovery ventilators, or on-demand hot water heaters.)
Off to a Good Start
“These guys in Kamloops have never tried building to a higher performance level; these houses have been built with their standard construction methods. They have been building houses without thinking about airtightness, and they are doing okay,” says Watson.
“They’re definitely reaching Step 1, and they aren’t making significant upgrades to get to Step 2 or Step 3.”
Ray Smith, another licensed energy advisor, is seeing similar results in the East Kootenays. He shared airtightness results for a series of new homes built back in 2016—well before the new standard came on the radar—using similarly conventional practices.
The three homes clocked in at 1.78, 2.07, and 2.28 ACH—meaning they would all meet the airtightness requirements of Step 3.
Again, good airtightness is just one of the requirements of the BC Energy Step Code. Beyond that, the home’s design will largely determine what, if any, investments a builder will needs to make to reach compliance, explains Watson.
Suggestions for Next Steps
A large house with multiple large dormer windows, bump-outs, and corners, will likely need more upgrade investments than a smaller one that has a simpler shape, fewer corners, and less glass. The latter home would more easily meet the requirements of the Lower Steps with few, if any, upgrades, says Watson.
“Considering additional insulation is an obvious one,” says Watson. “I often recommend adding a semi-rigid or rigid insulation to the outside of the walls. Lots of builders are doing that already.”
Watson also says that many builders are using insulated concrete forms for below-grade work “as a matter of course,” which is giving a real boost to the performance of basement walls.
As higher-energy efficiency requirements move from voluntary to required, builders will need to engage with an energy advisor, like Watson or Smith, at the very earliest stages of their projects. The advisors will help the builders keep those costs to a minimum.
As for Rose Choy, she said her members remain concerned with the cost premiums currently associated with delivering on the requirements of the Lower Steps—and the additional front-end paperwork requirements.
But, overall, she says, “the Step Code is do-able.”
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Glave Communications produced this post on behalf of the Training and Communications Subcommittee of the Energy Step Code Council, with resource support from BC Hydro. In an effort to increase awareness and understanding of the BC Energy Step Code, the Energy Step Code Council is sharing information on how and why builders and communities are using the new standard. Local governments may use the BC Energy Step Code, if they wish, to incentivize or require a level of energy efficiency in new construction that goes above and beyond the requirements of the BC Building Code.