The Ontario Ministry of Municipal Affairs has issued new guidelines to help builders reach Ontario Building Code energy efficiency targets for new small and large buildings, wrapping up a five-year process of consultation with the industry.
Smaller buildings such as single-family homes built from 2017 onward will have to be 15 per cent more energy efficient than the 2012 baseline and larger buildings have a 13 per cent target.
Ministry manager of building code policy development Chris Thompson explained that constructors tasked with building to meet the new energy efficiency targets have various options — Thompson refers to them as "recipes" — to achieve the new goals.
Two sets of Supplementary Standards have been issued with different mechanisms that builders can follow as they strive to reach the new targets.
In February 2016 the draft Supplementary Standard SB-12 for smaller buildings was released to the industry with those standards finalized in the summer. Then draft SB-10 standards for bigger buildings were circulated in September with the final version coming into effect in January.
Given that contractors and perhaps architects, but rarely engineers, design smaller buildings such as single-family residences, the SB-12 standards contain a set of prescriptions that can be followed by builders to reach the energy-efficiency targets along with four different performance paths, offering greater flexibility, that a builder can follow, Thompson said.
"If you look at SB-12 you can pick a range of different things," explained Thompson. "If you don’t want to do the insulation you can bump up the furnace and water heater, because there is a package for that, a recipe. So there are five different ways under SB-12 of complying with the code."
A different approach is taken with larger buildings, he said.
"SB-10, for large buildings, is performance-based, something that is usually handled by engineers and energy modellers and architects, so not a prescription so much," he said.
The SB-12 standards with the new prescriptive compliance packages will impact exterior insulation values and continuous insulation, window, door and skylight efficiency, space heating equipment and domestic water heaters, indicates the ministry.
Heat transfer is also addressed in SB-12 with HRV or ERV (heat recovery or energy recovery ventilators) systems now mandatory for all prescriptive compliance packages. Similarly, drain water heat recovery units are now required for prescriptive compliance packages.
The idea, said Thompson, is to save energy in both cases by using air and wastewater that have already been heated to help heat incoming potable water and incoming circulating air.
As buildings get more technically complex, he said, there is a significant challenge for the building trades to keep up and these kind of programs play an essential role in building the capacity of the sector.
"We are keeping them up to speed and we know it is a major effort, so you want to make sure that what you’re doing is actually happening in the real world," said Thompson.
"We want to keep it practical and sensible, as well as cost effective. We still want people to afford to have houses that are energy efficient and conserve water. It is a balance."
A typical single family home is inspected by municipal building code inspectors seven times during construction, said Thompson, so builders will learn early on if their efforts meet the new guidelines. The City of Thunder Bay recently launched an outreach effort to ensure local builders were aware of the new energy-efficiency requirements.