Chipotle built four stores, including this one in Gurnee, Ill., under a LEED pilot program for restaurants and retail stores. The Gurnee location has a whole-house energy-management system and generates some power via rooftop windmills.

Chipotle's commitment to green has only grown stronger. It has since incorporated eco-friendly elements into all its restaurants. More ambitiously, the chain plans to submit three restaurants, in Gurnee, Ill., Long Island, N.Y., and Minneapolis, for Leadership in Energy Efficiency and Design, or LEED, certification by the U.S. Green Building Council, a nonprofit dedicated to environmentally friendly construction. A fourth green-on-steroids unit was scheduled to open in March in Ballard, Wash.

"We do it for the same reason we started serving food from sustainable sources," says Chris Arnold, Chipotle spokesman. "It's the right thing to do."

Indeed it is, for several reasons, operators and experts say. As the green movement turns from fad to way of life, customers expect to see eco-friendly menus, operational touches such as biodegradable disposables, and buildings.

Expensive, eco-friendly reclaimed hickory makes a design statement at Sweetgreen in Washington, D.C. The cost means future locations will sport a single wall of the antique wood.

Chrzanowski says that architects and clients are considering other factors such as the life span and durability of a product, its recyclability and reusability, and its energy efficiency. "It's not just, 'it's a recycled material, good, I'm done,'" Chrzanowski says.

Besides, he adds, recycled isn't the last word in eco-friendly building. Many construction materials—stone, glass, certain types of wood—are naturally green. "Ceramic floor tile—that's a natural material," Chrzanowski says.

Pyrogrill executives chose a conventional floor sealant over doubts that the "green" product would be durable enough.

Budget counts as well: All materials decisions are made keeping the chain's average building cost, $900,000, in mind.

"Most people look at, what is the cost of doing a green building," Arnold says. "We looked at what we were spending, and what we could do within that existing budget."

The exceptions to the budget rule are the four LEED units, which were built under a U.S. Green Building Council pilot program for restaurants and retail stores, Arnold says. Those stores are more expensive to build, though he wouldn't be specific. However, "there's a substantial payback based on the systems in place," Arnold says. The first LEED buildings are designed to show Chipotle what measures will yield the highest return on investment.

Pyrogrill, a three-unit, fast-casual wrap concept based in Jupiter, Fla., also subscribes to the pay-now, save-later principle of green building.

Two of its restaurants use reclaimed wood for millwork, tankless water heaters, and low-VOC, or volatile organic compound, paints and finishes, says Michael Curcio, chief executive officer and founder. All three locations use high-efficiency light bulbs and photocells to control artificial light depending on the availability of natural light.

Curcio says such materials add 2 to 3 percent to building costs, "but it's made back in spades" in energy savings.

Still, he is choosy about green materials. For instance, the sealant on the stained-concrete floor is not low-VOC. "There wasn't very much information as to the durability it would provide," Curcio says. For durability's sake, he also opted for stained concrete flooring over recycled laminate or bamboo. "It needs to be durable," he says of the store's finishes. "That's first and foremost."

Sweetgreen executives found a contractor who would sort and recycle material from the enterior demolition at its first location, a 560-square-foot historical building in Washington,D.C.

Nicolas Jammet, co-founder of the fast-casual concept, and his business partners splurged on the hickory, salvaged from an old barn in Virginia and priced at $16 per square foot, to create a design "wow." The wood, Jammet says, adds a more organic feeling to the interior, in keeping with the chain's menu, made from sustainably grown food, and other green touches, such as biodegradable disposables.

A decorative panel of green and white leaves, made from recycled materials and printed with soy ink, completes the eco-friendly design package. The contractor also recycled materials from the interior demolition, Jammet says.

Sweetgreen's next two stores, scheduled to open this month in the D.C. area, will each measure 1,500 square feet, too big for the full hickory treatment. Instead, the back wall of each will be covered with hickory.

Jammet's ultimate goal is a LEED-certified building, which will match the concept's dedication to serving sustainably grown foods. Until then, "it's a learning process," he says. "Green is always an evolution. Every day you add something."

MORE: John Chrzanowski, partner and director of design at King-Casey Inc., a Westport, Conn.-based architect and design firm, gives first-step suggestions for moving toward environmentally friendly construction.