New Age Net-Zero

By Dan Vastyan

For decades, Janet Armstrong and Lloyd Davies have lived and breathed the sustainable lifestyle. Their way of life has ties to the example set by Armstrong’s father, who built the first solar house in Vancouver way back in 1978.

Armstrong and Davies lived in their first home in Vernon for 35 years, making many energy-conscious improvements over time. After retiring, they wanted a home that required less maintenance and offered an even smaller carbon footprint. “We explored moving, but we love our street and our neighbours, so we brainstormed,” said Davies. “Build a carriage house on the same property? No, too small. Tear down the old house and build new? Too much waste. We settled on moving the old house over, subdividing our lot and building a new house next door.”

The couple wanted the 2,600 sq. ft. home to blend in with others in the older neighbourhood while being energy efficient and sustainable. The craftsman-style residence includes an in-law suite, greenhouse, and wrap-around deck.
Rainwater from the standing-seam roof is used to water vegetable gardens and a 35-panel, 10.85 kW solar array provided 103 per cent of the home’s total energy needs last year—making it a net-zero residence.

“This home is a reflection of who we are,” said Davies. “We want to use it as a demonstration of what’s possible with modern building materials and techniques. Our hope is that people take something away and apply it to their own lives, ultimately raising the bar for sustainable living.”

Since the home was completed in mid-2019, the couple has hosted more than 250 tours, including individuals, colleges, and local organizations. “Visits have been limited during the pandemic,” said Davies. “But we’re looking forward to deeper involvement once restrictions are lifted.”

Tight construction

Armstrong and Davies chose Stonebridge Net Zero Construction Ltd. with their home over the 16-month construction period. The company’s owner, Albert VanEe, has been in the construction industry for 45 years, spending six of those years building homes in Japan.

“My business partner and I returned to Canada when nearby Kelowna suffered a devastating fire,” said VanEe. “We came back to build houses for people who were burned out of their homes. During our time in Japan, we learned a great deal about the Japanese aesthetic and making every square inch of a house count. This was a tremendous advantage at Armstrong and Davies’ house.”

The home was to be extremely comfortable, functional, and efficient, while also providing performance feedback through its control system for curious minds. Hardie Plank fibre cement siding is used on the home’s exterior, along with a standing seam metal roof. Exterior walls are double thickness with a half-inch gap between studs to minimize thermal bridging. Blown-in cellulose insulation fills the stud bays, and all wall penetrations were sealed for an airtight shell. On the outside of the plywood sheathing, Roxsul Comfort Board insulation was applied, bringing the exterior walls to roughly R-38.

Small details

The same attention to detail was applied to the foundation and slab. More than six inches of styrofoam insulation paired with a double vapour barrier are used under the home. Two-inch dense foam was used on the inside of the footings to isolate the slab. In the attic, an R-60 layer of cellulose insulation was blown in. All exterior doors and windows are triple pane, and were supplied by Innotech Windows + Doors, Inc., a manufacturer in British Columbia.

The ultra-tight construction provides a blower-door test rating of 0.59 air changes per hour (ACH). A similar home built to minimum local standards would typically have a rating of about 3.5 ACH.

Since a home needs fresh air infiltration to maintain a healthy living environment, the house has a fresh air system that includes a heat recovery ventilator (HRV) tied to a series of four earth tubes. This 10-inch diameter, high-density polyethylene tubes are buried between seven and nine feet deep along the foundation of the home. The soil temperature in the area remains at roughly 10C, preconditioning fresh air in the winter. It also provides the only source of air conditioning in the summer. This system, along with the home’s greywater recycling system, was designed by Trevor Butler, P.Eng., at Archineers Consulting Ltd. in Kelowna.

In the winter, the HRV further warms incoming fresh air by transferring heat from the outgoing air. This fresh air system runs continuously and acts as the only source of air conditioning during the summer. Discharge air from the HRV is blown over the outdoor portion of the heat pump, providing yet another source of waste heat utilization.

“An energy study revealed that the home is one of the most energy-efficient residences in Canada,” said Davies. “We even have a government certificate to
prove it.”

Total control

A 34,000 BTU Maritime Geothermal air-to-water heat pump supplies hot water to 10 zones of in-floor radiant heat. The basement slab includes hydronic tubing. The home’s wooden structure is rated to carry a three-inch slab of concrete on the second and third floors. There, hydronic tubing was fastened on top of the subfloor with concrete poured over.

Everything in the home is controlled by an extensive Tekmar control system. The Thermostats 553 and 557 control the radiant floor heating temperature and air-cooling temperatures. A House Control 406 operates the air-to-water heat pump and regulates the supply water temperature based upon outdoor reset.
Providing power to the thermostats and hydronic zone valves is a Wiring Center 313, and a tekmarNet Gateway 486 provides internet connectivity through a mobile app and website.

Additionally, 35 Tekmar sensors are used to measure and monitor building performance. These sensors, which are connected to a data acquisition system, are scattered throughout the home; on the floor, in the walls, and outside, which provide real-time feedback.

Uniquely British Columbian

While eccentricities can be found in various places throughout the home, one of its most unique features can be found on the roof. Here, a 300 sq. ft. terrace includes an outdoor shower for year-round use. Invisible to the neighbours, the shower is built with freeze-proof fixtures and has commanding views of Okanagan Lake and the mountains beyond.

A cold room is used to store fresh fruits, vegetables, and wine. It’s cooled by 39F (4C) discharge air from the home’s Rheem hybrid heat pump water heater. The room remains at 37F (3C) in the winter and 50F (10C) during the summer. A hot room with a large window on the second floor provides passive solar energy on sunny days no matter the season and warms a small greenhouse. Warm air generated in this room is circulated within the house by the HRV. There is also a passive solar hot water panel inside the hot room that provides preheated water to the water heater.

The home features the first locally approved greywater diversion system, often called “purple pipe,” which reduces the sewage flow by 60 per cent during spring, summer, and fall, when the landscape irrigation system runs.

As a final personal touch, the home features some building material from Armstrong’s father’s original solar house. These include a lovely, handcrafted set of kitchen cabinets, handmade doors, and several large, twin-seal windows from the old conservatory.

“Lots of hard work and sweat has built a wonderful home,” said Davies. “It’s warm where it needs to be, cool where it should be and very quiet because of the great windows, doors and insulation. This is our last house. Our costs to live here are very modest. We have no gas or electric bills. Our only expenses are city utilities, house insurance and city taxes. We love it.”