Building Science for a Net-Zero Future

Building Knowledge Canada
Written by Jen Hocken

Building science is the interaction of heat, air, and moisture with the built environment. As the world moves toward a greener future to help fend off the effects of climate change, we have to consider all the moving parts and avoid developing tunnel vision in the drive for efficiency and Building Knowledge Canada provides the necessary information.

In the field of energy conservation and construction, much emphasis is put on reducing carbon and greenhouse gas emissions. Although important, these issues must be examined in conjunction with the other components of the building. This is where building science makes a real difference by viewing the building as one whole system operating together.

When building science is not taken into consideration, it leads to unintended consequences. For example, when the energy crisis began in the 1970s, the first instinct was to pack insulation in the walls and ceilings. Within one to five years, these newly insulated enclosures experienced interstitial condensation, attic “rain” appeared and many more unintended consequences arose. In the 1980s, we finally figured out that if we are going to insulate and make the wall colder, then we would need to limit sources of moisture flowing from the interior to the exterior – hence the importance of air barriers and the adoption of air control layers into the National Building code of Canada in the late 1980s.

The story continued in the late 1980s into the early 1990s, when we saw insulated and airtight homes experiencing issues with indoor air quality due to lack of ventilation or fresh air. So the building science story goes: If you are to insulate, then you must make the enclosure airtight. If you make it airtight, then you need to ventilate correctly – and so forth. Unfortunately, the “rush” toward efficiency without first considering the building science resulted in indoor air quality issues, durability concerns and long-term damage to some structures.

The silver lining of this mishap is that it led to the development of building science: the study of the building as one fully functional system. Jump forward fifty years to today, and there are now several universities that offer degreed programs in building science including the University of Toronto, Ryerson University, and the University of British Columbia.

“That starts the history of building science. It’s looking at the performance of a home or building from a truly holistic perspective, considering the effect of design choices upon the built enclosure, the indoor environment and the occupant,” said Building Knowledge Canada Vice President and Director of Building Science Andrew Oding.

When an occupant looks to make their home more comfortable, they tend to focus on interior design finishes such as wall colour, flooring, cabinets, and furniture. The level of comfort connected with the superior air quality and durability based on building science are regrettably too often overlooked.

“When you truly apply building science principles first, followed then by energy or carbon reduction goals, the intended consequences are that you have an exceptionally healthy home which is comfortable, quiet, durable and affordable and simple to operate. It’s just a better lived environment and lived experience in the home,” said Building Knowledge Canada Marketing and Business Development Manager Stefanie Coleman. There is a direct correlation between designing for the occupant’s lived experience and energy efficiency when building science is kept in mind.

Building Knowledge Canada (BKC) provides building science services to homebuilders and renovators in three ways. It works with large development companies, builders of all sizes, renovators, and small custom builders to design and create affordable, healthy, comfortable, efficient, high-performing homes of any size. Secondly, BKC performs diagnostic testing for builders and renovators, offering a complete building science evaluation, which is far more substantive than a regular energy evaluation. The third aspect of BKC is focused on providing education, research, advocacy, and training to the home building industry.

BKC welcomes the opportunity to collaborate with others in the industry, particularly when providing educational services and has formed partnerships that have contributed to the high performance homebuilding industry. For example, with the support and sponsorship of Enbridge, BKC now hosts a webinar series that runs every month and offers free training for homebuilders, renovators and trade contractors in building science.

Given the unpredictability of 2020, there was initial concern that the construction industry would slow significantly. However, it ended up being a surprisingly busy year for many builders, especially in Ontario where the housing shortage is high. “There’s a housing supply issue, and it’s driving the demand for people to continue to build, so the market has stayed very steady and busy,” explained Coleman. As it was deemed an essential service, BKC can carry on providing energy design services and home performance testing (i.e. blower door testing, HVAC system analysis, enclosure reviews, air barrier inspections) and promoting the industry by following rigorous precautions and recommendations from the government and health departments.

The challenge for builders during the time of COVID is keeping up with supply issues in the market. Lumber has almost doubled in price, and there is also a shortage of necessary mechanical and plumbing equipment because of manufacturers having to shut down.

From an operational side, BKC has transferred its usual in-person meetings and training to an online setting through the use of technology and virtual interaction platforms. This has allowed the company to provide the same level of training and even expand its services with the previously mentioned new webinar series sponsored by Enbridge.

The construction industry is still experiencing a shortage of skilled trade workers and the building code regulations are raising the bar on energy conservation. This causes the cost of housing to rise, making it more challenging for people to purchase homes. One trend that has emerged to help address this dilemma is manufactured housing.

Manufactured houses are prefabricated in a factory and delivered in sections to be fit back together on site. Coleman expects that manufactured housing will grow in popularity over time, “Not only is it efficient from a construction perspective so that it can help manage costs, but also from a labour perspective, and there’s better control as far as how the homes are built,” she explains.

Throughout its history, BKC has helped to design or improve 55,000 residences using building science. The company also recently surpassed three hundred net-zero residences in the last four years.

The Canadian Home Builders’ Association’s (CHBA) qualified net-zero home labelling program is an energy rating label using Natural Resources Canada’s EnerGuide rating system. Homes with the Net-Zero Ready Home™ label must be designed and built to produce an amount of energy equal to the amount that they consume, using renewable energy sources. The CHBA has gone even further to support the improvement of Canada’s housing stock by developing a pilot net-zero energy renovation labelling program for builders looking to retrofit existing buildings.

In good timing with the industry, the Canadian federal government recently announced that it will invest several billion dollars into the existing housing market, and particularly to label an additional one million homes with the EnerGuide rating system. “Over one million homes have already been labelled, and they want to do an additional million homes. With fourteen million homes in total in Canada right now, that is a significant number. So we will continue to see, in the next while, a real emphasis on addressing energy conservation in the existing housing stock,” said Coleman.

Canada investing in the EnerGuide rating system is a success for the industry, and the goal of labelling an additional one million homes is a great step forward. Hopefully, the trend will continue until every home in Canada has gone through the EnerGuide rating system. The benefits to both builders and homeowners are clear.

New national building codes are steadily moving toward net-zero ready. A proposed tiered energy code (wherein tier five is essentially net-zero ready-like) under the National Building Code of Canada is set for publication near the end of 2021. South of the border in the U.S., the recent model national energy code for houses, IECC 2021, is essentially equivalent to net-zero energy ready homes. Nearly 27 U.S. states already require blower door testing of every home simply to obtain occupancy permit. Homes today are nearly fifty to sixty percent more efficient than homes built in the early 2000s.

One marketplace challenge that builders face is that new high-performance homes are competing in the market with older homes, and without a clear “efficiency rating” label from the EnerGuide rating system, there is no baseline for the homeowner or building owner to use for comparison.

“If you have a food label or an energy-efficient label, now the homeowner has a way to make the decision. It’s no different than the rating on the car for economy and mileage and fuel efficiency. We’re very big proponents of putting something on all homes so the consumer can make smart decisions,” said Oding.

Having a consistent label on all homes gives consumers a way to make direct comparisons, and this information should always be provided when purchasing an asset as large as a home or building. Unfortunately, some groups have opposed the idea of rating every home with the EnerGuide rating system, possibly for fear that it will undervalue some older homes on the market. However, this should not be a significant deterrent because a buyer can already look at the utility costs of the home to get a basic idea of how inefficient it is. The EnerGuide rating would simply make this information transparent and show exactly which areas need to be upgraded.

“On the EnerGuide label, it actually tells the homeowner what to do specifically to that home if you want to increase efficiency. Whether it’s the windows or the attic insulation or the airtightness or if the furnace needs to be upgraded,” explained Oding. “That’s the beauty of the EnerGuide label that the average Canadian doesn’t know.”

Other sceptics of the labelling system say that it is too costly and there are not enough energy auditors to complete the work, but that is not true. “The Canadian Association of Consulting Energy Advisors CACEA ( has already been working at the provincial and federal level, and there are enough accredited energy advisors now to service all of Canada. So let’s go!” said Oding.

BKC is currently the senior building science consultant for the national net-zero energy multi-unit residential buildings pilot developed jointly by the CHBA and Natural Resources Canada. The pilot consists of seven multi-family developments across four climate zones in Canada constructing net-zero multi-family buildings applying modular housing technology. Expected to be complete within two years, the purpose of these projects is to develop affordable energy-efficient housing by lowering the cost of construction.

Thanks to the application of building science principles, net-zero homes are capable of providing a superior indoor air quality, comfort and quietness that has to be experienced to truly understand. “There’s no comparison. I use the example of heated seats in the car; you don’t know you need them until you’ve experienced them. Once you’ve experienced them, you just can’t live without it, and that’s how I feel about a net-zero-ready home now,” explained Coleman.

In the construction industry, builders have seen a continuous increase in soft costs which are the additional costs not directly related to construction. These are sometimes overlooked when discussing why affordability is an issue in the housing stock. “The cost of land, the cost of permits, and development charges far outstrip the rising cost of materials and labour,” said Oding. “When you look at the items that have increased the most over the last ten to fifteen years, it is more the development fees and the permitting than it is the hard cost of the home, and I think that’s a real concern for the builders and the development community.”

These rising costs, often associated with improving efficiency, are all-too-frequently built into new construction costs and put on the backs of the builders or new home buyers. There needs to be more dialogue between municipalities, councils, and developers to achieve the goal of net-zero homes all across Canada as it is vital to have a mutual understanding surrounding the built-in cost of advancing the industry.

“What we have found to be successful is when the municipalities collaborate with the builders and developers,” said Oding. For instance, if a developer can build a highly-efficient community or series of buildings and significantly reduce the load on the existing infrastructure and the requirements for water and energy, the city should be willing to support the project. “Whether it be by a decrease in development charges or a decrease in infrastructure costs, there has to be give and take on both sides.”



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