Pushing the limits of green

Please don't call it the greenest home on the planet," says Steve Glenn of his house in Santa Monica, California. "A yurt or a mud hut in Africa might be the greenest home on the planet not this house."

One can understand why he's reluctant to boast about the place, which he built in April 2006 and has inhabited for the past year. Critics are quick to pounce on claims relating to environmental achievements and, since this is not only a home but also the prototype for Glenn's company, Living Homes, there's more than his personal reputation on the line.

Still, last summer, the house did receive unprecedented validation from the US Green Building Council, becoming the first residential project to receive the group's highest Platinum rating for Leadership in Energy and Environmental Design. Another accolade came last month when it was the only non-institutional building included in the American Institute of Architects' annual list of Top Ten Green Projects. And Business Week magazine has, in fact, called it "the greenest house on the planet".

"You have to embody a spirit of market transformation to do this it's not just a case of finding a different kind of flooring," says Ann Edminster, former co-chairman of the LEED For Homes initiative, who was Glenn's point of contact in the certification process. "There was a lot of learning along the way but the end result is uncompromised."

William Browning, an expert on green building and a partner at Terrapin Bright Green, which provides consultation on sustainable building to governments and companies, agrees. "What you are looking at is still rare. There are only a handful of houses that are working on these ideas."

Sustainability was Glenn's primary focus from the very start of the project, even factoring in his decision about where to build. He chose Santa Monica partly because he liked the area but also because he found an infill site that was within easy reach of public transport, shops and open spaces; in this case, a beach is just a short walk away. Low site impact, the preservation of open spaces and the importance of community are all integral to the green building movement.

The two-storey, 2,500 sq ft structure was not built so much as "installed", with local residents treated to the spectacle of 11 factory-assembled modules being lowered on to a concrete slab by a 350-tonne crane over just eight hours. A somewhat mesmerising time-lapse video of the entire installation can be seen on the Living Homes website, .

Prefabricated or modular homes are more efficient than traditional homes because they produce less construction waste; about 2 per cent of materials end up in a landfill versus 40 per cent. They're also more adaptable. Glenn, for example, could create an extra bedroom, open up a living space or add an outside deck just by putting in a new floor plate, moving an optional wall or changing the position of a sliding wall panel. The cost financial and environmental compares favourably to remodelling or building an extension.

Yet the house is far from a bog standard series of boxes. Built on a frame of largely recycled steel and wrapped with swathes of plate glass and cedar wood cladding, its contemporary style stands out on a street of unassuming bungalows and stucco cottages in a quiet neighbourhood west of Los Angeles. Designed by Ray Kappe, founder of the Southern California Institute of Architecture and a highly regarded modernist, it is made up of intersecting planes with an open-plan layout and views to the upper level from the ground floor. The play of sunlight across the straight lines and the plentiful use of wood lend warmth to the interiors.

"This is a green home that doesn't look like you need to eat a bowl of granola when you walk in the door," Browning says. "It's a beautifully designed contemporary home."