A new study by the World Business Council for Sustainable Development (WBCSD) finds that key players in real estate and construction misjudge the costs and benefits of “green” buildings, creating a major barrier to more energy efficiency in the building sector.

Respondents to a 1,400 person global survey estimated the additional cost of building green at 17 percent above conventional construction, more than triple the true cost difference of about 5 percent.

At the same time, survey respondents put greenhouse gas emissions by buildings at 19 percent of world total, while the actual number is 40 percent.

The report, “Energy Efficiency in Buildings: Business Realities and Opportunities,” summarizes the first phase of the WBCSD’s Energy Efficiency in Buildings Project, a three-year initiative to assess the environmental impacts of buildings and develop means to achieve zero net energy use for residential and commercial buildings. Zero net energy buildings will reduce demand by design, be highly efficient and generate at least as much energy as they consume.

About 80 percent to 85 percent of the total energy consumption and CO2 emissions of a building comes from occupancy through heating, cooling, ventilation and hot water use, according to Bruno Lafont, chairman and CEO of Lafarge. “Combining the right materials when designing a building envelope can greatly reduce a building’s energy requirements, increase its life span and ensure consistent performance over time.”

The project is co-chaired by Hartford, Conn.-based United Technologies Corp. and French building materials company Lafarge.

For a downloadable copy of the report, visit www.wbcsd.org.