When the Cascadia Region Green Building Council, a chapter of the United States and Canadian Green Building Councils (USGBC and CaGBC), launched its Living Building Challenge in 2006, the organization was positive that it had developed the first truly universal, holistic, sustainable building rating system in the world—with more stringent requirements than even LEED Platinum certification.

Cascadia wasn't entirely confident about its program's cost effectiveness, however, and didn't know how differences in geography, building size, or building type would affect payback periods. So the organization commissioned a financial study by a team of cost-estimating experts, the results of which were released recently.

Written by Cascadia CEO Jason F. McLennan, LEED AP, former principal of BNIM Architects, contributor to several industry magazines, and founder and CEO of Ecotone Publishing, the Living Building Challenge rating system consists of 16 prerequisites for designing any new or renovating any existing building type that generates its own power and harvests, treats, and reuses its water for net-zero energy and near-net-zero water performance; uses sustainable materials; is durable; provides a healthy indoor environment; chooses its site responsibly and minimizes site impact; and is beautiful. Certification as a Living Building is based on verification of actual building performance over a 12-month period, rather than on points awarded for design.

"It's very hard to achieve, but it's actually a very simple system," McLennan says. "A lot of the designers who are using the program like that it's very simple and elegant. It puts emphasis on actual performance of the project." The intention is not to compete with the LEED rating system, but to offer an additional method for promoting and achieving the sustainability goals set by the USGBC and CaGBC.

"The Living Building Financial Study" examined the construction documents of nine actual projects that have been certified LEED Gold: a school, a home, a high-rise mixed-use facility, a multifamily project, low-rise and mid-rise offices, a university classroom, a mixed-use renovation, and a hospital. The study team—led by SERA Architects with Skanska USA Building, Gerding Edlen Development, the New Buildings Institute, and Interface Engineering—modified the construction documents of these already green buildings to meet Living Building Challenge version 1.3 prerequisites in four different climate zones (one hot and humid, one hot and arid, one temperate, and one cool), then repriced the buildings based on the modifications to compare the cost difference between LEED Gold and Living Building.