RALEIGH - With its waterless urinals, motion-detecting lights and formaldehyde-free-plywood recycling bins, the future headquarters of Cherokee Investment Partners has all the earmarks of a brand new "green" building -- the kind more developers are touting these days as they get in touch with Mother Earth.

But the bones of the 21,500-square-foot office are anything but new. The office is in a sprawling brick building that dates to 1870.

Cherokee is among a growing number of tenants converting leased space in old buildings to environmentally friendly offices.

"We need to be thinking about the environmental impact of what gets built and energy use and energy waste," said Cherokee CEO Tom Darden. "This is one place where we thought we could do something about it."

In 2000, the U.S. Green Building Council established the Leadership in Energy and Environmental Design (or LEED) Green Building Rating System to promote construction of environmentally friendly and energy efficient buildings.

Builders could earn points toward LEED certification by using recycled building materials, incorporating systems that conserve water and electricity and using shading and lighting in ways to reduce dependence on heating and air conditioning.

But the system largely applied to developers of new buildings. It was harder for tenants to achieve LEED certification for their little corner of a building. "There were too many things out of their control," said Juliana Strieff, an architectural consultant for landlord Empire Properties, a partner with Cherokee in the renovation.

So in 2004, the building council created a new rating that allowed tenants to be LEED certified in buildings that aren't.

Commercial interiors now make up about one in 10 of the nation's 6,300 projects that are LEED certified or seeking certification. There are 105 LEED certified commercial interiors, up from 40 in 2005. At least 542 more are seeking certification, including three in the Triangle. They are vying to become the first in the state to earn the distinction.

The building in which Cherokee is leasing, the former Heilig Levine furniture store at Wilmington and Hargett streets, is one.

Like many old buildings, its old-fashioned light bulbs sucked energy, faucets leaked or could be left on, and windows let in drafts.

Cherokee's space, when finished this month, will have fluorescent lights, faucets that turn off by themselves and sealed windows.

Bicycle racks and showers encourage employees to drive less; a computer server helps heat offices; toilets flush 1.28 gallons instead of the 2.5 gallons sucked by previous bowls; paints give off few vapors. Contractors even used an organic pesticide to kill bugs in recycled-pine baseboards.

Developers and tenants often shy away from green construction because the building materials are often pricier than traditional, mass-produced products.

Systems that regulate energy consumption can drive up prices. It's not unusual for an LEED upfit to cost 20 percent more than a traditional job, contractors say.

Those who take the plunge expect to recoup the premium largely through utility savings.

Many pioneers are companies whose images benefit or are reflected by LEED certification. Cherokee specializes in buying contaminated properties and cleaning them up to sell to developers. "Not doing it would seem out of character," Darden said.

SmithGroup is seeking LEED certification for its 3,000-square-foot office at the American Tobacco Historic District in downtown Durham. The architecture and engineering firm hopes to be 20 percent more energy efficient in part by using a system that gauges daylight in the office to determine whether the lights need to be on. But not everything is so high-tech, said SmithGroup's office director, Chris Brasier.

"From the start, there's environmental benefits to renovating and finding new life in an existing building," he said of his office in the former tobacco warehouse.

That's why the green building council also made a LEED certification specifically for existing buildings. It accounts for challenges faced in old buildings such as Duke University's Smith Warehouse, which earned the state's first and only existing-building certification in 2004. It's one of 42 nationwide, and at least 262 more are seeking certification.

Greenfire Development wants LEED certification for three buildings it plans to renovate at City Hall Plaza, Mangum and Parrish streets in downtown Durham.

It will also aim for certification when it renovates the nearby SunTrust tower. It could use a system to catch stormwater and use it in the tower's plumbing.

"It's not just a trend, it's the way buildings should be built," Greenfire partner Michael Lemanski said. "It's hard to demonstrate that you're committed to the environment if you're not willing to lead. No pun intended."