Nelson City Council has adjusted the energy efficiency requirements for new houses and small buildings in Nelson.
As of August, builders have two choices. They must meet Step 4 of the BC Energy Step Code, or Step 3 if they already meet the “strong” level of B.C.’s Zero Carbon Step Code.
These two codes measure different things. The BC Energy Step Code measures the air-tightness of buildings, whereas the Zero Carbon Step Code measures the amount of carbon emissions from a building resulting from heating or cooling.
Nelson has instituted these changes partly as a response to increased standards recently included in the provincial building code that require a minimum of Step 3 in residential and smaller buildings under three storeys as of May 1. Nelson began requiring Step 3 in 2021, and its move to Step 4 now keeps it ahead of the provincial standard.
These rules apply to buildings three storeys and under with a footprint of 600 square metres or less.
The city’s climate resilience planner Natalie Douglas realizes the meaning and details of these measures are potentially confusing to the public and to builders.
“It’s a lot of stuff,” she says. “When you look at the two codes and try to get your head around what the standards are for each one, it’s a lot.”
But she clarifies that although initially it might seem complicated, implementing it is not so hard because decarbonizing heating or hot water systems “is not novel.” Douglas cited the increasing popularity of heat pumps as one established solution.
“Based on our engagement with builders, what we have proposed is realistic and achievable,” she said.
Douglas said the reason for the change is that it helps the city reduce its greenhouse gas emissions.
“This is a priority of the city and is a consideration that must continue to inform our building policies.”
Nelson’s climate action plan Nelson Next recognizes that buildings and transportation are the largest emitters of greenhouse gases in municipalities and calls for emissions reductions in both.
“I’ve been very pleasantly surprised with how much buy-in we have from builders,” she said.
“Most builders said that they liked being ahead of the curve. Many builders articulated a personal desire to be ambitious, a sense that this level of ambition is closely associated with how Nelson sees itself as a community.”
She said most builders enjoy the fact that they are already in compliance and did not feel rushed into changes.
B.C. Energy Step Code
The air tightness of a new building is planned using software modelling in conjunction with the services of a specialized energy advisor. When construction is finished, air tightness is tested by a measuring device known as a blower door test.
For residential and smaller buildings the code consists of a series of five steps, each with increasingly advanced energy saving standards. Step 1 was the status quo as of 2018, Step 2 means increasing efficiency above the status quo by 10 per cent, Step 3 by 20 per cent, and Step 4 by 40 per cent. The fifth step is a net-zero-ready building that has potential to produce as much energy as it uses once a renewable energy system has been installed. (Some wood frame residential buildings accomplish this in four steps.)
Nelson has been ahead of the game on this: the city instituted Step 3 in 2021, and city planners at the time noted that many local contractors were already building to that standard or above it. So with its move to Step 4 now, the city will still have a higher standard than the province.
The standard in Nelson for larger more complex buildings is now Step 2 and Douglas says this has yet to be updated.
If there are emissions from a new residence, however minimal, the code does not deal with the nature of those emissions, which could be fossil fuel emissions. That is where the BC Zero Carbon Step Code comes in.
This code is about the electrification of buildings and aims for no greenhouse gas emissions from houses. Its three stages are moderate, strong (the alternative offered by the city, see paragraph two), and zero carbon performance.
The level labelled “moderate” allows for fossil fuel water heating and cooking but all else must be electric. “Strong” still allows fossil fuel cooking but eliminates fossil fuel heating. “Zero” means all systems are electric.
Left out of the equations in the two codes described above is embodied carbon — the greenhouse gas emissions arising from the extraction and manufacturing of building materials such as concrete, foam insulation and steel. This carbon adds to the footprint of a building even before its actual construction.
So far neither the city nor the province has any rules about this, but the City of Nelson has recently completed significant local research into embodied carbon and has published an emissions guide that can be read at https://bit.ly/3MdAthL. The research for the guide was funded by FortisBC.
Nelson Next names the reduction of embodied carbon in buildings as a priority.