Spirit of the Sun: A Solar Rastra Home in California

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Diagram of the first floor

Between the two of them, John Schaeffer and Nancy Hensley have forty years of experience researching green building, off-the-grid living, and permaculture. John founded Real Goods, the nation’s first solar retail business, in 1978 in Hopland, California. Nancy has lived off the grid since 1973 and joined Real Goods in 1989. The couple has realized their dream of employing their collective wisdom to create an energy-independent, nontoxic, environmentally gentle home that promotes sustainability—while also being tastefully beautiful and soul soothing.

They were right on track with that vision as construction on their 2,900-square-foot roundhouse—oriented to the cardinal directions and patterned after a red-tailed hawk ready to take flight—began in early 2001. The home is set on 320 acres overlooking the Hopland Valley that’s richly landscaped with gardens, orchards, ponds, a lake, and a grotto with a waterfall. In 2002, John and Nancy moved into a barn on their property where they could watch the building progress. That summer, they noticed several large, black birds pecking mercilessly at the windows. How cute, they thought, until they realized that weeks later the birds—ravens—continued to attack the home’s sixty-nine windows with a vengeance.

“We went into major raven research mode,” Nancy says. “We talked to biologists, ornithologists, and shamans. People told us to dance around in circles with corn, build altars, give them offerings. We eventually learned that when the birds are nesting, they’re very territorial. They saw their reflections and tried to scare off those ‘other ravens.’”

“A shaman told us the ravens were upset because we were calling the house Sunhawk—they have a natural animosity toward hawks,” John says. “So we made an altar and for thirty days we brought them tobacco, fish, and meat.” In marked contrast to locals who thought a shotgun was the answer to their raven problem, John and Nancy’s attitude was that the birds had inhabited this piece of land first and that they, as the human “intruders,” should strive to live in harmony with the ravens. That open-mindedness translated into every step of building their ecologically friendly home.

Better Living Through Technology

Built from Rastra blocks, which are made from 85 percent recycled polystyrene beads and 15 percent cement, Sunhawk is a masterful example of sustainability. Nancy spent months researching building materials and appliances. Her finds include recycled-tire roof shingles and repurposed granite countertops from a Berkeley café. Roof decking, fascia, barge rafters, and beams were made from reclaimed redwood, Douglas fir, and walnut from an area winery, vinegar plant, warehouse, and a converted orchard.

John and Nancy’s house is, of course, entirely off the grid. (Who would expect less from a renewable energy pioneer?) A seventeen-kilowatt solar system—recycled from a Gaiam Real Goods installation in Belize blown down in a hurricane—provides ample power in summer months, and a hydroelectric turbine produces 1.5 kilowatts per hour from a seasonal creek that runs through the property from December through May. “Our hydro system provides thirty-six kilowatt hours per day—almost twice the national average for electricity use,” John points out. “And it cost only $1,500—it’s way more cost effective than the electric company or any other source of electricity. It’s a powerful feeling knowing we’ll never have to pay an electric bill for the rest of our lives.”

John is most proud of the home’s innovative heating and cooling systems, which work so well largely because of the passive heating and cooling design. Cooling the house without air conditioning is no small feat in Hopland, where summer temperatures consistently rise to three digits. In Sunhawk’s central core, rocks are buried nine feet into the earth, where the temperature is a consistent 67 degrees Fahrenheit. Two solar-powered fans pull this cool air up culverts and into the central core, where it travels by convection to the rest of the house. Even on the hottest day, the home’s interior has never exceeded 76 degrees Fahrenheit. The home is heated primarily by radiant floor tubing powered by rooftop solar hot-water panels and water heated by the excess voltage from the solar and hydroelectric systems.

Living off the grid entails absolutely no sacrifice, John quickly points out. In fact, there are unexpected bonuses. “We got a satellite system for Internet access, and it’s two to three times as fast as DSL or cable,” he says. “The fun part is we get to use our house as a laboratory for the technology and products we order for Gaiam Real Goods.”

Now, This is Permaculture

After John and Nancy bought their acreage in 1998, they spent numerous nights camping in various places around their property to find the ideal spot for their house—in the end, exactly the location where Nancy’s intuition had initially told her it should be.

Building the Real Goods Solar Living Center in Hopland had taught the couple the importance of landscaping as an integral part of designing a homestead, so they made that a priority—even before finding a designer for the house. “We knew early on that this would become much more than just a house-building project,” John says.

Their first major project after grading the road was to dig a ten-acre-foot lake flanked by a thirty-foot-wide grotto overflowing with waterfalls from the property’s three natural springs. Three-and-a-half acres of lush permaculture landscaping include native grasses, a coastal redwood grove, Mediterranean foliage, lavenders, and a corridor of swamp cypress by the pond, which attracts a variety of wildlife including herons, egrets, ducks, coots, and giant bull frogs. To complement the landscaping, the couple added fruit and nut trees and Italian olive trees from which they hope to make their own olive oil. The orchards and the pond are key to the home’s comfort; prevailing winds from the northwest flow across them and bring evaporative cooling inside.

The grounds continue to be a work in progress. Four Rastra window boxes on the home’s south side provide enough growing area to keep the couple well fed. Vegetable beds are located six feet from the kitchen door so John and Nancy can step outside in any kind of weather to harvest arugula, cilantro, and exotic lettuces. Recently, as part of a Real Goods Solar Living Center permaculture workshop, students spent four days building an herb spiral on the home’s north side and installing a composting system, worm bin, and drip watering systems.

Letting the Hawk Soar

With the major landscaping in place, John and Nancy faced the task—and privilege—of creating a house that could live up to their ideals. “A home is far more than a shelter,” John says. “It’s an expression of our values and commitment, and it enables us to put our convictions into action. We wanted ours to promote not just the principles of sustainability, but to engender restoration and regeneration of the environment, while also nourishing the spirit.”

They searched until they found architect Craig Henritzy of Berkeley, who understood that vision. However, they were taken aback when he showed them a set of plans for a Rastra house based loosely on the California Native American roundhouse (in the style of the indigenous Pomo Indians) and symbolic of the hawk—which he declared John and Nancy’s “house totem.” “We thought it was visionary and unique, but a real challenge to pull off in a practical sense,” John admits. Being open minded, John and Nancy visited another roundhouse Henritzy had designed in Napa, and they knew they’d found their architect. “That house was unlike any other we’d ever seen,” John says. “It felt Native American yet twenty-second century—both ancient and futuristic.”

“For Native Americans, the hawk symbolizes ‘vision,’ which has been important in John and Nancy’s work,” Henritzy explains. “Also, in the ‘green architecture’ field we often use just shed-type designs, which I feel has limited the progress of alternative designs being accepted in the housing market. This design explores passive solar with a geometry that celebrates the sun’s cycles and playfully and beautifully assumes a hawk shape.”

Because Rastra’s Styrofoam beads give it a fluid quality, it’s easily cut and sculpted, making the hawk shape and orientation with the cardinal directions possible. Sunlight falling on a solar calendar running from north to south on the living room floor marks the passing seasons. On the winter solstice, sunbeams stream through a stained-glass hawk above the south-facing French doors, causing the bird to “fly” across the floor from west to east. At exactly solar noon, the sun illuminates a slate hawk in the floor in front of the living room woodstove.

“I appreciate always knowing the position of the sun,” John says. And that, Nancy adds, is really just a fringe benefit of a good passive solar design. “The very basic, most important thing is good southern exposure—taking advantage of sun and light,” she points out. “What I love most is that the sun comes in at the right time and doesn’t come in at the wrong time.” 

Sunhawk: The Basics

House construction

Rastra block (85 percent recycled Styrofoam, 15 percent cement)

Foundation and Rastra block grout

Six-sack concrete and fly ash mix reinforced with rebar


Seventeen-kilowatt photovoltaics (4 kW AstroPower 110w modules and 13 kW Siemens 75w modules), Harris hydroelectric turbine

A Conversation with the Homeowners

What do you love most about this house?

Nancy: I love the feeling of permanence and belonging. European houses are frequently homes to families for a thousand years. I see no reason ours won’t be here to see our newly planted redwood trees turn 1,000 years old.

John: There’s nothing better than walking with bare feet on the warm floors on a cold winter day and curling up in the cushions in the south-facing window seats.

What’s your favorite room?

Nancy: In the dining room we can sit atthe table and enjoy 360-degree views of the pond and the wildlife. We keep a bird guide and binoculars on the dining room table.

John: I love having a great “dishwashing” window in the kitchen where I can look out over the valley while I work. And of course there’s the tower where we hold great solstice rituals.

What would you do differently?

Nancy: I would have created a hazardous materials collection station when we began building and introduced all the subcontractors to it. You don’t want even nontoxic paints and sealers ending up in the landfill or your future garden.

John: I would be more patient. When you’re going to live in a home for decades, who cares if it takes an extra six months to complete? I’d spend more time and think out every detail. It’s easier to change things before the house is done.

What advice can you offer new home builders?

Nancy: Include the outside areas in your planning. We just recently poured the sidewalks around the house, so we had a year of mud and dust. Don’t wait until the house is done—do it at the same time.

John: Erect your solar system before you start construction. That way you build with solar energy and don’t have to listen to and smell generators—and you save money in the long run.