The house was designed with a long east-west axis to maximize winter solar gain. Large south-facing windows allow winter sun to warm the 50% fly-ash concrete floors, which absorb heat in their thermal mass during the day and slowly release it at night.

In the summertime, deep roof overhangs shade the interior, and mini-blinds sandwiched between the panes of the double-glazed Pella windows can be adjusted to block the sun. Shaded from the summer sun, the thermal mass of the floor absorbs coolness from the earth beneath it and helps to keep the house comfortable. Cross ventilation, which admits ocean breezes through low windows on the western wall and vents them out high windows on the east, keeps the house cool.

The passive solar design is just one of the many energy-saving and environmentally conscious measures built into this home. The owner, an avid birdwatcher, is accustomed to stepping lightly on the land and fitting inconspicuously into the natural world. So when she and her husband decided to build a new house in the 15-acre orange grove they had owned since 1985, “We tried to make it as green as possible.”

Inspired by the annual Parade of Green Buildings tour in Santa Barbara, they began planning the house in 1999. Their first concept, using the rammed-earth technique common throughout the world, was rejected by the Ventura County Building and Safety Department. So they decided to work with Allen Associates, a Santa Barbara firm that has been designated one of the top green builders in the country by American Builders Quarterly Magazine. The owners worked with contractor Jim Morledge of Allen Associates to see how green they could get using more conventional techniques.

“There are many shades of green,” the owner says with a smile.

Putting water to work.Water and climate control systems have been integrated. The floors are further warmed by a hydronic radiant system divided into zones controlled by separate thermostats. The water is heated by a propane-fired tankless water heater—at least until a planned upgrade to solar-heated water can be made.

In the summer, cold water can circulate through the same PEX tubing within the floors—cooling the house before flowing on out to irrigate the landscaping.

Energy and lighting. Other energy-saving features include low-voltage track lighting and a 4.95 kW photovoltaic system mounted on a detached barn, which provides all the electricity the home needs plus a bit extra for the grid. Large windows plus frosted glass in interior and closet doors spread natural light throughout the house, minimizing need for daytime lights.

“A lot of this is just common sense,” says the owner, guiding visitors through the bright and welcoming rooms.

Smart materials. Rather than conventional “stick” framing, the house uses a steel post-and-beam framework and exterior walls and roof built with Structural Insulated Panels (SIPs), which sandwich a thick layer of foam between two layers of formaldehyde-free oriented strand board (OSB). These provide excellent insulation and withstand seismic forces better than conventional framing. It was the first experience with SIPs for Morledge and crew, but they found the material easy to work with after they arranged a little coaching.

“The SIPs supplier referred us to a company in Northern California that had worked with the product,” Morledge says. “They sent down two trainers to work with us for a couple of days.” After that, the pieces went together smoothly.

The steel standing-seam roof contains recycled content and the rain it catches is collected in a rain barrel for use in the garden.

Wherever possible, the owners opted for materials that were recycled or less toxic: kitchen cabinets of formaldehyde-free Medite II fiberboard, SlateScape fiber-cement countertops, bathroom tile with a high recycled-glass content, no- or low-VOC paints and adhesives. And all appliances are ENERGY STAR-rated.

“We’ve dreamed of building a house like this for a long time,” the owner says. Although they had some regrets about sacrificing some of their Valencia orange trees to create the site, “We decided that if we were going to build a house in an orange grove we were going to do it well.”