Spiraling energy costs are a major factor driving demand to build and occupy sustainable green buildings, based on a recent survey of architects.

Last week, Autodesk Inc. and the American Institute of Architects (AIA) unveiled their 2007 Green Index. Roughly 70% of the respondents indicated that client demand for reduced operating costs is the leading motivation behind green building. Architects are responding by incorporating sustainable elements such as high-efficiency HVAC systems and recycled building materials into their designs.

“The results of the survey are encouraging,” says Christine McEntee, executive vice president and CEO for the AIA. “But there needs to be a greater sense of urgency to make sustainable design the norm in the profession.”

Buildings are the leading source of greenhouse emissions, reports the AIA. McEntee and the AIA have set a goal to reduce carbon emissions from member buildings by 50% over the next three years. A longer-range goal is to achieve “carbon neutrality” by 2030.

AIA members are well positioned to see that goal through: According to the survey, 88% of respondents have received training or continuing education focused on green building practices.

Many architects have already put that knowledge to use, too. During the past five years, for example, the number of architects using high-efficiency HVAC systems in their projects posted a 25% jump. The use of highly reflective roofing materials also increased by 18% since 2002 while energy modeling and analysis adoption climbed by 17% in that period.

“We are encouraged that the 2007 Green Index shows a growing number of architects practicing green building,” says Phil Bernstein, a vice president at Autodesk. “Since only 10% of architects are currently measuring the carbon footprint of their projects, Autodesk recognizes a need to make this an easier and more efficient process using new and existing technology solutions.”

The Autodesk/AIA Green Index was conducted online in October. A total of 347 practicing architects based in the U.S. were polled. The breakdown of their specialties: 44% are “predominately” involved with commercial projects, 32% with institutional projects and 20% with single-family homes. The remaining 4% of respondents design industrial projects.