Planting a solar home in a forest without losing the trees

A solar home can work with the sun and integrate with the forest, too. When Betty and Dwight Busby decided to put a solar system on their wooded lot in Flagstaff, Ariz., it suggested the dilemma of trees shading the solar collectors, or else having to cut the beautiful ponderosa pines that are part of the lot's attaction.

MR. Busby, the energy-conscious president of the Arizona Planning Association , held out for a happy coupling. his approach was to "watch their relationship and get their points of view."

To get the sun's perspective, he took aerial photographs that showed where tree shadows fell across a natural clearing halfway down the slope of the property. By siting the solar collector in the clearing where there was a minimum of shadow, only one tree had to be cut.

There were other challenges in designing for this lot. For one, the lost sloped down from the road, facing north. A solar collector must face southM. In this case, it must be at the front of the house, thus dominating the entrance. Nevertheless, Mr. Busby set out to design a residence that both integrated with its setting and whose solar-heating system was effective in the high mountainous climate.

To ensure effectiveness, he opted for 540 square feet of collector surface, employing high-efficeincy solar panels stacked in vertical columns to conserve lot space and avoid shadows. the result was a collector 20 feet wide by 33 feet high, its vertical form aesthetically paralleling the surrounding pines.

By carrying the vertical approach through in the house -- three stories stacked back to back with the collector -- each level has wide views north: down to a golf course green at the foot of the hill, across to forest treetops, and up to Mt. Eldon's peak at 9,200 feet.

three bedroons and two baths occupy the lower floors. The living-dining-kitchen areas are on top, not only for the eagle's view, but also to allow the warm air rising through the house to keep the sleeping levels cooler and the sitting level warmer. the first and third floors open onto outdoor decks for squirrel watching and sunbathing.

At east and west elevations the chimney and stairwell are housed in rounded redwood enclosures that flank the high vertical lines of the house with a symmetry of curves.

The third-floor living area is linked to the road at the top of the hill with -- what else? -- a covered bridge. Bridging to a garage at roadside removes the need for a driveway and related snow shoveling and provides a 60-foot entrance with a curved transparent acrylic cover.

Under the garage, between the floor and the downgrade, there is a storage room and an office for Mr. Busby, which supplement the house's 1,900 square feet of living space.

Mrs. Busby sees her new residence, which companios slope and view, sun and forest, as "a perfect marriage of the scenes."

The same thoughtfulness went into engineering the hot-air solar heating system. Air heated behind the solar panels is blown down to a rock pit under the house for storage or directly to rooms through a duct system. a return system channels cooled air, from storage and house, back to the solar panels for reheating.

Efficiency features for heat storage include small rock size, a vertical pit, and a total absorption sensor. a thermostat automatically controls the circulation of hot air among the collector, storage area, and house.

Hot air also heats water for the house by passing across a heating coil in the duct system.

Mr. Busby expects the system to provide 100 percent of heating needs during six months of the year and 60 percent in Decemrecord of continuous operation, I spent a coldweather weekend there and experienced the system firsthand.

Even though the outdoor temperature dipped far below freezing during the night, solar-heat storage in the rocks satisfied a second-floor thermostat setting at 62 degrees until 3 a.m., when the gas heater kicked on. In the morning, the thermostat was raised to 72 degrees to warm the bedrooms. By 10 a.m. the solar system took over completely with the outside temperature still in the teens.

The top floor was always cozy in the 70s, mostly from convection and periodic fire in the fireplace. The hot-air vent in the living room was unneeded. Hot water was plentiful.

The only unwanted development was a toowide temperature difference between the floors, which Mr. Busby has corrected by insulating the underside of the first floor and the insides of the foundation walls.

During construction, the house not only attracted the curious in its summer-winter recreational community but, according to Mrs. Busby: "People who have comparable lots in the neighborhood came by to look and talk and have taken new interest in what can be done with their own property."

There were even offers to buy the house before it was finished, but the Busbys said no. For them, it is a long-cherished idea whose time has come.