A Net-Zero Luxury Home for Aging-in-Place Integrates Geothermal and Solar 

Located on 15 acres near Ridgefield, Washington, the four-bedroom home has 4,500 square feet of one-level living.

The foyer, two bedrooms, a media room, and a home office are on the same level as 1,600 square feet of outdoor living areas (300 square feet of the outdoor space is covered), for aging-in-place with seamless access to the outdoors, gardens, and native vegetation. The home's 1,500-square-foot upper includes two bedrooms and a bonus room above the garage.

The home's "unique look," Johns says, was inspired by a golf resort in southern Oregon. "When we visited the golf resort, we were struck by the architecture and wanted something similar for our new home." 

The Johns' home received Emerald-level certification from the Home Innovation Research Lab's National Green Building Standard (NGBS). "That's NGBS' highest possible rate and the most rigorous to achieve," Johns says. With its net-zero energy efficiency and repurposed materials, the home sets a new standard for healthy, conscious luxury. 

Air-Tight Building Envelope and Solar Electricity 

The builders constructed the home with two-foot-on-center framing and local timber frame trusses. The foundation incorporates radon mitigation with vents and a crawl fan. They achieved the tight building envelope of R-50 walls and an R-60 ceiling with standard batt insulation and blown-in closed-cell spray foam. 

The water lines of the geothermal system run throughout the acreage, Johns says. "The system is super-efficient and uses very little electricity." The electricity the home does use is generated by a 76-panel, 28.2 kW photovoltaic system. Energy is stored in three Tesla batteries. The solar array "generates four to five megawatts per two weeks in the summer, and much less in the winter," he says.

The house is 90 percent electric, he adds. "One bathroom has a propane hot-water heater so, if we lose power, we have enough to keep the showers going for a while." The kitchen stove is also propane. "Everything else is electric," Johns says, and the appliances are ENERGY STAR rated.

Two heat-recovery ventilators (HRVs) exchange stale indoor air with fresh outdoor air. They also transfer heat from one air stream to the other. The HRVs then circulate the pre-heated or pre-cooled fresh outdoor air throughout the house. Johns chose Lifebreath HRVs, which he says "provide excellent air quality." The home also includes two Aprilaire electric air cleaners. 

There is, however, an adjustment the HRVs made possible. "The geothermal heated floors are tile and toasty and warm. But we're always learning," he explains. "We figured out that when you build a house so airtight, it doesn't lose a lot of heat, and the floors don't kick on. Now we have a comfortable home, but the floor can be slightly cool. HRVs, however, help circulate the air and kick the floors back on. Without the HRVs, the floor would stay cold."

While the Johns' built their forever home "to show people they can build a luxury home that's net-zero and incorporates sustainable features, the reality is that anybody can do this," says Troy Johns. Including builders. 

"We'd like to see more builders get on board. We're constantly encouraging people to try just one aspect of sustainability if they don't want to go net-zero. The prices would go down on so many technologies if more people incorporated them into their homes."

There's also the bigger picture in light of climate change. "The type of energy-efficient, sustainable construction we're doing on a global scale," he says, "would have a huge impact on the planet. We could see a real change in people's attitudes toward reducing their environmental impact."