Using Net Zero tech to build better multi-unit residential buildings

June 25, 2020

The Canadian Home Builders’ Association has embarked on an exciting mission: to provide healthier homes for Canadians using the fastest and most efficient methods, including Net Zero technologies.

“It is considered the crème de la crème of building performance levels right now because it incorporates the best of building science and it’s led by industry,” says Marie Hanchet, CHBA Net Zero Energy Housing Project Manager.

The National Affordable Housing Corporation's Willowview Heights was one of the first multi-unit residential buildings (MURB) qualified under the CHBA Net Zero Ready Home Labelling Program, and Big Blocked helped NAHC get that qualification.

The foundation of Willowview Heights uses insulated concrete forms, one of the many energy-efficient features of the building. Read about laying the foundation for the building.

Hanchet says the voluntary Net Zero and Net Zero Ready Home Labelling Program is an opportunity to help leaders in the industry identify solutions in a new building type.

The industry has been learning what it takes to make it to Net Zero in single family for years. Now is the time to bring that knowledge to multi-unit residential buildings.

“There are unique challenges and opportunities with multi-unit residential buildings,” Hanchet says. “The units are smaller in general but there are the same number of occupants living in the unit — this changes the energy intensity. People are doing the same things in their home but occupying less space.”

There are also challenges finding mechanical systems that deliver the right amount of heat to all units.

But it’s worth it to overcome these challenges.

Affordable homes for everyone

CHBA wants MURBs that are affordable and comfortable for the people living there, and can be replicated.

“What’s the point of having a home that nobody can afford?” Hanchet asks. “The more we can drive down the cost of construction, the more people who can access home ownership.”

On top of that, the operating costs are lower because the energy performance is so much better. Modular builds, like Willowview Heights, are another opportunity to use scale to reduce the energy bills.

That scalability of modular builds is also important to a project like this because it’s a system that can be repeated.

A comfortable Net Zero house

Perhaps most important, though, is comfort.

“Environmental performance on its own is great but great energy performance is not worth it if people are freezing in winter or boiling in summer,” Hanchet says.

A critical piece to finding solutions that are comfortable is monitoring. The energy models most builders use are reliable but they’re not as accurate as they could be.

This project will help gather more detailed data on how the homes are actually performing and how people feel in their home over time, Hanchet says.

“Unless you’ve monitored the performance, you won’t know that you’re achieving what you intended to.”

Willowview Heights and other projects like it will have five-year monitoring of the home, along with check-ins with the builders about levels of comfort.

On top of informing industry leaders, the data will be shared with the primary funder of the project, Natural Resources Canada.

Step by step to the future

The first stage of the project was design, which included a national design charette with industry leaders and partners from all over the country. Big Block also led its own design process locally.

The second stage was building the project.

The third stage included a cost analysis of the project, comparing it to the current practices, to figure out what level of savings are possible on a mass scale. 

“An incredible level of attention to detail is required for a Net Zero energy multi-unit residential building.”

The last stage will include a cross-country knowledge dissemination and education program to bring the learnings to the industry as a whole.

It’s not easy taking on a project like this, and Hanchet says the CHBA is impressed with the dedication of partners like Big Block.

“We want to thank Big Block for taking on the challenge of bringing their buildings to the Net Zero Ready label,” Hanchet said. “An incredible level of attention to detail is required for a Net Zero energy multi-unit residential building.”

Construction of Willowview Heights has been made possible through a financial contribution from Natural Resources Canada.

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