In Washington, D.C., thousands of visitors stream through the “Green House” exhibit every week at the National Building Museum. It's on track to become the museum's most popular exhibit. Meanwhile, millions of Americans watched recently as This Old House transformed a 1926 Austin bungalow into an eco-friendly home.

It's official: Green has gone mainstream. As This Old House producer Deborah Hood says, people no longer need view green as experimental or expensive. “We're learning that green is basically just good planning and smart building.” And green remodelers echo that sentiment. They're as likely to use words such as “high-performance” when talking about their green work, so interwoven are the concepts.

Green remodeling, loosely defined, refers to building for energy efficiency, water conservation, and healthier indoor air quality; using products and materials that are sustainable; and reusing or recycling materials rather than dumping more waste into a landfill.

Different corners of the country play up different aspects of that definition, though. One of the basic principles of green building is to tailor strategy by region. So, for example, in California, reusing and recycling is key, since there's no more room in landfills. In New Mexico, water conservation is a critical focus. And the farther north you go, the more insulation factors in.

Consumers are driving the growing green trend for a number of reasons, among them the need to rein in soaring energy costs, the threat of global warming, and mounting health concerns — particularly for the one-in-13 children with asthma, a condition aggravated by poor indoor air quality.

In some parts of the country, legislation is spurring the need for energy-efficient buildings, as well. In Boulder, Colo., for example, residents will soon be charged a carbon tax based on how much electricity they use, prompting many to make updates to old, drafty homes. In Montgomery County, Md., new legislation requires public and some private construction to be LEED-certified.

Some state governments are also moving toward green reform. In California, the Air Resources Board is considering standards that would ban toxic substances such as formaldehyde, which is present in cabinetry, pressed wood products, glues, and adhesives. (The state already has Title 24, establishing energy-efficiency standards for construction.) And in Massachusetts, legislation passed last summer bans certain demolition debris from landfills.

By enacting legislation, green practices are being moved from the fringe to the mainstream, state by state. As electricity demands strain power plants and as landfills fill up, that trend will likely spread across the country. And remodelers who haven't yet come onboard may soon be forced to do so.

BETTER BUILDING “Green has absolutely exploded,” says David Johnston, a Denver-based green-building consultant and author of Green Remodeling: Changing the World One Room at a Time. “There's a market demand for it on all levels, both building and remodeling.”

But are remodelers ready? “Consumers are interested way beyond the industry's ability to respond, especially the remodeling industry,” Johnston says. “They're about five years ahead of us, which is why there's sort of a scramble among remodelers to catch up.”

One way remodelers are playing catch-up is by attending conferences, such as the GreenBuild conference, which drew more than 13,000 building professionals to Denver last fall, far more than the 10,000 who attended the previous year. Another is through continuing education.

Michael McCutcheon of McCutcheon Construction in Berkeley, Calif., says that, if anything, the green movement is encouraging remodelers to take their game to a higher level through education and third-party certification programs. The National Association of the Remodeling Industry (NARI) started a pilot training program in green remodeling this fall, and many local green programs offer training courses, as well. A number of those courses are geared toward experienced remodelers looking for a deeper understanding of building science.

For example, McCutcheon recently attended an advanced continuing-education class through Build It Green (www.builditgreen.org), a West Coast green-building program. They spent almost an entire day talking about waterproofing. “We talked about the exact right way to waterproof certain details on a building,” McCutcheon says. “Everyone learned from it. And this was in the advanced class. The point is, the fundamentals of this industry are still poorly understood.”

The waterproofing discussion underscores McCutcheon's belief that the green movement will raise the bar for the entire trade. In other words, building green is ultimately about building better. “If we can waterproof correctly, the building lasts longer. That's green. Green is really just best practices,” he says.“I don't believe that if you're not doing straw-bale construction, you're not green. That precludes the rest of us from taking baby steps.” And everyone has to start somewhere.

STARTING POINTS Indeed, while consumers around the country are raring to go, green remodeling has only been aggressively embraced by contractors in pockets where local green-building programs or legislation exist — areas such as Seattle, Boulder, the San Francisco Bay Area, and Austin, Texas. “Remodelers in those markets really have taken the lead,” Johnston says.

Holding remodelers back, in many cases, are perceptions that green remodeling is too expensive, that the materials are too time-consuming to work with, that the subject matter is too esoteric. For a long time, remodelers have taken for granted construction materials and methods that use non-renewable materials and energy sources, hold up poorly over time, and contribute to indoor air pollution. A structure that isn't built to last will be demolished too soon, adding more waste to landfills and demanding new resources for rebuilding. “Reversing the course” means rethinking the process from start to finish.

Yet other remodelers say they're ready to embrace green building, but feel they've been left behind. For example, LEED certification (offered by the U.S.Green Building Council) only applies to new construction. And there's currently no national green certification for remodelers, although that's changing. NARI announced it will launch a certification program this fall — and immediately after the announcement, there were 120 people on the waiting list. The industry seems poised to jump into the mainstream with both feet.

Green remodeling may be a trend, McCutcheon says, but it isn't a fleeting one. “Green building is really just smart building. We've been doing these same things for 25 years, only now we're calling it green,” he says. “We've been saving people money, choosing products that last, and finding the most beautiful solutions.”

In the pages that follow, experts and remodelers talk about why the time is right to join the green movement, how to get employees and subcontractors to incorporate green practices into their routines, how to sell the green approach to clients, and what to do with all those reusable building materials from the job you're working on now. In short, you'll have a good sense of what comes next in the greening of your business. Because chances are, even if you're still on the sidelines of this movement, you won't be for long.

Reasonable Objections As they stand at the crossroads, considering whether or not to join the green movement, remodelers are sometimes faced with a tough choice: Abandon the old, familiar way of doing things? Or do it the green (not necessarily easy) way?

Take the purchasing of lumber, for example.

Twenty years ago, it was easy for builders to get 2x4s from old-growth forests. The wood was straight, and unlikely to warp. But today, 95% of the nation's indigenous trees have been cut. Forests have been replaced by fast-growing tree farms that yield lumber that twists and cracks.

Alternatives do exist, such as reclaimed lumber, engineered lumber, SIPs, and Forest Stewardship Council-certified wood, which is selectively cut and pesticide-free.

The argument: It's hard for remodelers in many parts of the country to purchase FSC-certified wood or some of those other green alternatives. Lumberyards don't carry it. Maybe they have a contract with a competing product, and there's only so much space on their aisles. Or, even if lumberyards do carry it, it comes at a premium. It's easier to buy what's affordable and on the lot.

True enough. To take a step toward green building, though, remodelers will have to pressure lumberyards to carry the products they want, or go straight to the manufacturers themselves, say green advocates. When there's enough market pressure, high-quality FSC-certified wood will become widely available, and the forests will stop being pillaged. And that, ultimately, will help curb the effect of greenhouse gases and global warming.

In other words, remodelers hold the power to change things. And some believe it's time to use that power.

Alice Bumgarner is a freelance writer based in Durham, N.C. When she's not covering the remodeling industry, she writes about food, travel, and parenting. Her work has been published in Salon, Sky, and Town & Country magazines, among others.