The Higgins are at the forefront of a boom in green building.

Much of it is being driven by a generation of young professionals interested in anything "earth friendly" to create their own urban oasis. Call them GUPPYS - green urban professionals who are young.

In some respects, it is the 1970s all over again, except its adherents wear Merrills instead of earth shoes and bamboo floors and recycled glass counters have replaced woodstoves and solar panels as signature elements.

And perhaps nowhere does the fervor take on a deeper shade of green than in the Pacific Northwest, in cities from San Francisco to Seattle, where the climate is relatively mild and environmentalism is a virtual religion. Indeed, Portland, Ore. - which already draws a large number of 25- to 34-year-olds - may be the new capital of the ecohouse movement.

"A lot of people move here seeking many things, not the least of which is life in a greener place," says Ethan Seltzer, professor of urban studies and planning at Portland State University. "Oregonians may not be getting the biggest paychecks, but they are getting access to a natural environment that provides them with a lot of benefits. So it's not surprising that you see more solar lighting and eco roofs here."

Well-educated young people are disproportionately drawn to Portland, according to Joe Cortright, economist and coauthor of "Young and Restless: How Portland Competes for Talent," a study of the migration of 25- to 34-year-olds across the US. "In focus groups people said Portland is a place where you can live your values, and environmentalism is clearly one of them."

Mr. Cortright sees this playing out across the country as well. In places where young professionals are migrating - Portland, Ore.; Phoenix; and Charlotte, N.C., to name a few - the job market gets extremely tight, forcing much of the creativity into entrepreneurial positions. It is those people who may push the mounting interest in building green over the edge and into mainstream.

Many young professionals looking to buy or build their first house - or empty-nesters wanting to downsize or remodel - see building green as much more than a movement. It's a responsibility, and it's becoming irresistibly chic.

"Building green is both a very practical, self-interested activity, in terms of lower operating costs, and it also has a deeper spiritual value to many people taking responsibility for the impacts they have," says Alan Scott, an architect in Portland who has been involved in the green building movement for years.

Portland groups such as City Repair, which brings several hundred people together to work on natural building projects dotted around the city, have tapped a market that is clearly on the upswing.

Part of its allure is that "green" is no easy name to come by. It is akin to a status symbol, and it must be earned. Even the Higgins hesitate to call their house green, despite its many environmentally sensitive features.

Aiming for 'net zero energy' spent

A green building must attempt to produce net zero energy, which many achieve through solar paneling, eco roofs, and smaller spaces. It must use mostly recycled or renewable materials - anything from glass countertops and used lumber to wool carpeting and bamboo floors. Even the energy spent to transport the material to the site is considered; recycled glass, for instance, loses its "conservation" value if a lot of fuel was used to haul it there.

It is no surprise, then, that green homes are less accessible to those who cannot afford the pricier materials and construction expertise. It is still the domain of the wealthy - or at least yuppies with disposable income.

But as the owners of green homes know firsthand, the cost difference is largely superficial. Any up-front costs are recaptured over time because these buildings use so little energy. Portland General Electric, for instance, reimburses houses that generate more power than they use. An award-winning green house in Cannon Beach, Ore., with its solar panels and eco roof (a roof planted with greenery to deflect heat and improve insulation), is actually making money this spring.

"There are such significant selling advantages to building a green building that if the up-front cost differential is eliminated you will see a lot more green development taking place," says Leanne Tobias, founder of Malachite LLC, a venture founded to provide services on sustainable or green development in Washington, D.C.

"As energy prices continue to inflate, the advantages for building green become even greater," she says. "Green building will be mainstreamed, a far greater share of new construction will be green construction, and there will be a great deal of interest in retrofitting existing buildings so that they are more energy efficient."

More resources available

Though such breakthroughs as solar paneling and eco roofs have been in the works since the '70s, actual adaptation has been slow. Even five years ago the kinds of recycled materials available today weren't on the market. But California's energy crisis, the 2003 blackout in the Eastern US, along with swelling gasoline costs, have served as a wake-up call to homebuyers.

"[We are being] forced, in a good way, to take note and be proactively involved [in green building], says Darr Hashempour, vice president of energy solutions for PinnacleOne, a construction consulting firm in Los Angeles. "This isn't a fad. Building green is now a fact of life."

Not everyone characterizes the green momentum in such optimistic terms. "There clearly is an upward swing, but if you're talking about any real penetration into the mainstream, I don't think there's been any," says Lester Lave, an economics professor and director of the Carnegie Mellon Green Design Initiative in Pittsburgh.