When the Cascadia Region Green Building Council, a chapter of the U.S. and Canadian Green Building Councils (USGBC and CaGBC), launched its Living Building Challenge in 2006, the organization was positive 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 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.

"We were surprised to see how comparable [our program] is in many of the building types studied, and how in several instances nothing but Living Buildings make financial sense," McLennan says. 

The study found that Living Buildings can cost as little as 4% more and up to 49%percent more, with payback periods ranging from as little as two years to as many as 44 years, depending on type and location. For example, the financial argument for Living Building-designed university classroom buildings was very strong, particularly in the temperate climate zone: a 4% to 9% cost premium and a two- to three-year payback period. 

As might be expected, Living Building single-family residences have some of the highest cost premiums and the longest payback periods, with the lowest cost premiums (26% to 31%) occurring in the temperate climate zone and the shortest payback periods (22 years to 27 years) occurring in the cool climate zone. For homeowners planning to stay in their homes for two or more decades and willing to accept longer payback periods, the Living Building Challenge rating system could make sense. Multifamily residential buildings performed similarly in the study.

The full results of “The Living Building Challenge Financial Study,” including an executive summary and a matrix of building types, climate zones, cost premiums, and payback periods, are available for download here.

Notably, the Living Building concept has already spread outside of the United States, with projects in Canada, Mexico, and France considering following the program. To further promote Living Buildings and the rating system and to serve interested parties globally, Cascadia announced the establishment of the International Living Building Institute [www.ilbi.org] during its 2009 Living Future Conference, held May 6-8. 

Version 2.0 of the Living Building Challenge is scheduled for release in November. According to McLennan, it will be fully scalable from single-family residences all the way up to neighborhood, campus, and community design.

Stephani L. Miller is Associate Web Editor for Custom Home and residential architect magazines.