Comox Harbour Home Receives a Net-Zero Retrofit

Colin and Nadine had been living in Vancouver, British Columbia, with their two children for a while when they realized they were ready "to make the shift to something small town," Colin says. "We wanted to get out of the rat race of the big city," adds Nadine. "That was our motivation in moving. But we also were feeling more and more like we wanted to make a difference and become more environmentally sustainable with the house we chose to move to."

Their goal, with the new house they would choose, was "to get our carbon footprint to net-zero," Colin says. "The move was the catalyst for making a difference." They shopped around, finally deciding on a west-coast homestead looking out toward Comox Harbour. "We knew we wanted to be close to the water, but we're also cognizant of storm surges and rising water levels with climate change," Colin says. The family also wanted to be able to walk to the town center for shopping, dining, and entertainment.

The house, built in 1976, fit the bill. But it needed work. The existing structure had two small bedrooms, no garage, and a medium-size living, dining, and kitchen area, which wasn't enough square footage for the family. Colin also needed an office as he works at home as a marketing professional with a large software company.

"We went through the questions many homeowners needing to renovate ask themselves," says Colin. "Do we renovate? Tear it down? We knew we had to add square footage." There was also the matter of retrofitting the house for maximum energy efficiency. "We knew we wanted a net-zero or passive house," he adds. "None of our friends were doing this, so we had to take a risk."

The family went online and found Pheasant Hills Homes, Ltd., a high-performance builder in Nanaimo, on Vancouver Island, which focuses on passive and net-zero. After lots of discussions and budgets, "we felt confident in the abilities and what they cautioned us against," Colin says. "We're happy they did the build."

Surpassing Air-Tightness Targets

Colin and Nadine, with help from their design and build team, realized that renovating the existing structure to meet Passive House standards would be tough. So, they worked to find a balance between renovation and new construction to reach their goals. "You have to think upfront about materials you plan to use, where the windows will go, how they'll bring in heat, how the walls will retain that heat, and so on," Colin says.

According to the Canadian Home Builders' Association, net-zero homes produce as much clean energy as they consume. Net-zero homes are up to 80% more energy-efficient than typical new residential construction and use renewable energy to create whatever additional power is needed. In keeping with this, Colin stated, "For us, getting to a zero-carbon footprint could be done more easily and with less risk by installing solar—while also making the house energy efficient."

Systems and components throughout the home are well-integrated to ensure consistent temperatures, prevent drafts, and filter indoor air. The result is superior energy performance and comfort; in other words, a home at the forefront of sustainability.

To keep as many materials as possible out of landfills, the team saved about 40% of the existing house. They saved the foundation and about 25% of the existing walls. "A lot of the joists and rafters were in good shape," Colin says. After the structure was complete, the team inserted five different types of insulation. These included spray foam in the walls and the basement, fiberglass in the walls, blown-in insulation in the attic, comfort board, and mineral wool.

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The workers tightly taped all of the joints. After the addition of Euroline triple-pane windows, the team invited Capital Home Energy of Vancouver to test the home's air-tightness. Air leakage can be detected by depressurizing the home to quantify the ACH (air changes per hour). Capital Home Energy taped up an exterior door and attached their blower door fan to begin the test. The home exceeded expectations with 0.58 ACH @ 50Pa. When compared to the BC Step Code targets (Step 5 = 1 ACH), the net-zero home target (1.5 ACH), and the Passive House target (0.60 ACH), this was a significant accomplishment.

Achieving a Net Zero-Carbon Footprint

To produce energy, the family went with on-grid solar panels: 32 Canadian Solar 355W split-cell poly-crystalline modules that produce 11.4KW or 12.45MWh annually. "The orientation of the house was already toward the south along the main part of the rooflines," Colin says.

Because the family moved in July 2019, and the panels were not installed until September, they haven't yet been able to fully document their energy use and savings. "But we can see, in terms of the modeling Pheasant Hills did, that we're on track to be net-zero," Nadine says. Already, they enjoy watching, via the information provided by BC Hydro, how much energy they're producing and using. When the family produces more electricity than is needed to power their house, it goes back to the BC Hydro utility grid. "And we get paid for that," Colin says.

Durable, Local and Efficient Features

The home has a long-lasting metal roof. It utilizes a Daikin central heat pump, Rheem Marathon 75-gallon hot-water heater, a heat recovery ventilation system, and a heat recovery system for the master bathroom drain water. The family also "checked all the boxes," Colin says by using LED lighting, low-flow toilets, and Energy Star appliances.

The maple flooring was farmed and cut in BC. The dining-room table was custom crafted from a bowling alley lane: "There's a company on Vancouver Island that cuts and ships the wood to you," Nadine explains.

The home also has cedar soffits, stone counters, and a chestnut-wood island countertop. Wood reclaimed from an old barn serves as a unique mantle over the fireplaces, which are gas. "We don't need the fireplaces for heating, but we love using them during the cold and wintry months," Colin says, "and they serve as a backup heating system should the power go out."

A retaining wall creates a yard for the family, separating the home from marsh and brush along the shoreline. The house is also outfitted with a Tesla charger in the garage, and universal-level 2 EV charger on the home's exterior.

Energy Efficiency Now for the Future 

While the neighborhood was fascinated by the home's transformation from a small, weathered cottage to a stunning, high-performance home, Nadine and Colin's kids were equally intrigued. "They're definitely into sustainability," Colin says. "They feel proud that, as a family, we're doing something proactive about their future by renovating a home to be net-zero."

According to Nadine, the kids are also pleased the family drives an electric car, which they had before retrofitting the house. "The electric car was the first thing that hit home," she says. "We're not adding carbon to the atmosphere when we drive, and the kids feel good about that."

Adds Colin, "They've done projects, written essays, and given talks in front of their classes in which the subject is the electric car or sustainability. They are ambassadors with their friends about the importance of it all."

Article by:

Camille LeFevre

Camille LeFevre is an architecture and design writer based in the Twin Cities.