"We're on our way to having one of the greenest buildings in the United States," says Jeff Golden, cofounder, with his partner, Kavitha Rao, of Common Fire Foundation, an organization devoted to improving the world. When the couple set out to build a cooperative housing project near Tivoli, in northern Dutchess County, their intention was to be kind to the environment while providing a home with a nurturing atmosphere for people doing important social or environmental work in the area.

"We wanted the building to reflect the integrity and commitment these people demonstrate in their daily lives," Golden wrote in an essay titled "Confessions of a Green Enthusiast" that appeared last year in this magazine. Although their goal was not to win a competition, they discovered that their diligent efforts to choose environmentally sound materials and practices were likely to make their project the first building in New York State to achieve platinum certification with the U.S. Green Building Council.

The cooperative nearly complete.

During the last year, Golden and Rao and their collaborators—designer Chuck Silver of Hudson River Design, and builder Doug Hoffman of Eco-Con Building Systems—have brought Common Fire's high ideals to fruition. On a sunny spring day, Golden offered a tour of the building, then just a few weeks away from completion.

As we turn off a country road near the hamlet of Tivoli, we pass a row of graceful gray birches separating the long driveway from the fields of the neighboring farm, with great patches of yellow mustard flowers lining the woods on the opposite side. We wind along a series of gentle curves to a small parking area, screened from the house by trees.

Of the 53 acres purchased by Common Fire here, 25 have been put under a conservation easement, which means they will remain "forever wild." Two eight-acre parcels have been sold as building sites to help fund the project, with deed restrictions that require the owners to build green. From every window in the house are views of wild greenery. The house itself looks no different from most homes. But looks can be deceiving.

"The building will use 50 percent less energy than a regular building of comparable size and use," says Golden. To achieve such a high of conservation, the building envelope uses insulated concrete walls in the basement and structural insulated panels (SIPs) in the second-floor walls.

Cofounders Jeff Golden and Kavitha Rao.

All the building's electricity needs are generated from a 12.6kW photovoltaic system. Five ground-mounted panels are placed due north of the building. Because the panels can be adjusted seasonally to follow the sun's rise and fall, the system gains 15 percent efficiency, which makes it work like a 14.5kw system. This solar panels supply electricity to run a geothermal system that provides heating and cooling.

The L-shaped house is built into a hill on its north side, and on its south side is oriented to optimize passive solar gain, with a multitude of large windows. Rooms are protected from the rays of the midday summer sun by three-foot-deep eaves (which admit only the lower-angled rays of winter).

The windows and doors, furnished at a significant discount by Pella, the project's premier sponsor, are the most highly insulated on the market. In addition to providing passive solar heat in winter and the aesthetic beauty of sun-drenched living spaces, the glass means never having to turn on a light in the daytime—even in the basement. To that end, five Solatubes, long, curved shafts lined with reflective material, channel an impressive amount of sunlight from the roof to the basement and the entrance hall.