The revised Building Bylaw was adopted on September 9 by councillors. The City says the new standards for residential buildings are roughly 25-percent higher than those set out in the industry-standard 2015 National Building Code.
Commercial buildings must now meet the standards of the 2017 National Energy Code of Canada for Buildings.
In a news release, the City said one key change involves the use of effective instead of nominal R-values, "which takes into account the cumulative value of thermal resistance for all materials within the assembly.”
R-values measure how well different types of insulation work.
The City said the old minimum insulation values have been removed from its new rules. They are replaced by National Building Code standards people must now meet if they upgrade, add to, or otherwise alter their homes.
According to the City, increasing its energy efficiency requirements will lower both the cost of living and greenhouse gas emissions.
EnerGuide 80 rating
September's approval of the new system follows two years of scrutiny regarding the rules Yellowknife builders must use when it comes to energy efficiency.
On June 25, 2018, city councillors voted to remove the EnerGuide 80 rating from the bylaw. That standard had been in place since 2010 but the federal government planned to remove support for EnerGuide 80 from January 2019.
At the time, councillors in favour of dropping the standard said it would be unenforceable without federal support.
Then-Mayor Mark Heyck, however, advocated for keeping the EnerGuide 80 standard until a replacement was found.
Heyck – now executive director of the Arctic Energy Alliance, which specializes in energy efficiency measures – said at the time: "It would be much better to say we have got this standard, we are working on it, we are going to engage with industry, and then we are going to bring out a new standard."
Reached on Tuesday, Heyck said he was pleased the City had reinstituted energy efficiency standards after a year or so without them.
"The City has done a good job of reaching out to gather opinions locally but also looking nationally and provincially," said Heyck, calling the new rules "a positive step forward."
He added: "With any change like this, the true test is when it's actually implemented and you have builders going through that process."
Heyck expects the next version of Canada's National Building Code to have enhanced energy efficiency standards, which is likely to mean more work for the City in future to ensure local regulations are consistent with the federal approach.
Asked if he felt Yellowknife had seen any impact from its year without energy efficiency standards, Heyck said: "It's difficult to say. The majority of Yellowknife's new housing is manufactured homes, so that process won't change dramatically just because a standard has been removed in the last 18 months.
"Hopefully it didn't affect the overall stock too much."
Ollie Williams contributed reporting.