By Kate Galbraith

Building green costs an average of 2.5 percent more up front, a study sponsored by the US Green Building Council and other real-estate and architectural groups has found.

The study, whose results were released to coincide with a major green-building conference in Boston this week, says that the premium is far less than the public believes. It surveyed about 150 buildings (mainly LEED commercial buildings, as rated by the Green Building Council, plus a few multi-unit residential buildings), and found that the median cost increase was 1.6 percent.

The resulting energy efficiency and water savings - which are not counted in the initial price premium - make green building economically worthwhile, the study argues.

"Five years ago building green was viewed as risky," said Greg Kats, the lead author and managing director of Good Energies, a company that invests in renewables and efficiency, in an e-mail message. "Costs were higher, there were few green buildings and not much experience with building them. Today we have a large body of data that show green cost premiums are actually quite small and that the payback is relatively quick."

"Energy savings alone, for example (assuming energy prices rise more slowly than in the past 4 years), offsets the average cost premium in five to eight years," he added.

When told of the study, some experts cautioned that the cost differentials are hard to measure.

Declaring that green buildings are 1.6 percent more expensive is "sort of like saying a fuel-efficient car is 2 percent more in cost than a regular car," said Peter Pfeiffer, a green architect based in Austin, in an e-mail message. He noted that many other factors could affect cost.

"My experience is that the features built into a home or building that are green-related (i.e., make it more durable, healthy, energy-efficient) can add as little as 1 percent to as much as 5 percent," Mr. Pfeiffer continued.

The study found the median energy savings to be 33 percent a year, which is higher than some other recent studies, but a key benefit in any case, architects contend.

"Study after study has shown that green buildings are frequently better buildings. They should use less energy, be more durable, and be healthier for occupants," said Richard Renner, an architect based in Maine, in an e-mail message.

Green Inc. has viewed the complete study, which is entitled "Greening Buildings and Communities: Costs and Benefits," but it is still being edited and will not be released in full until next year.

Source url: http://greeninc.blogs.nytimes.com/2008/11/20/debating-the-green-building-premium/