When you enter a LEED-certified building, even without knowing its history, you may notice right away that the space feels different. There's an abundance of natural lighting, the air smells fresh, and perhaps the space has a certain quietude, thanks to the higher ceilings and the absence of rumbling air conditioners.
What does LEED accreditation mean and what impact is it having on American construction?
An acronym for Leadership in Energy & Environmental Design, LEED is a "measuring stick" for the green or sustainable quality of a new or renovated building, explains Scott Wing, head of the architecture department at Penn State.
"The LEED rating system encompasses many factors, such as choice of building site, water efficiency, effect on atmosphere, and indoor environmental quality," explains Wing. "The innovation category allows for endless building system advancements in material, mechanical, and lighting performance that minimize energy and resource use. Ultimately, the goal is to reduce the 'embodied energy' of a building, that is, all the energy required to fabricate, ship, and install building components as well as operate the completed product."
The U.S. Green Building Council (USGBC) created the LEED system in 1998. A building earns points based on the number and types of design features that meet the system's sustainability criteria. Depending on how many points a building earns, it receives LEED certification on one of four levels, from the lowest level, "certified," to the highest, "platinum."
Penn State's own Stuckeman Family Building, home of the School of Architecture and Landscape Architecture (SALA), earned an impressive LEED Gold rating, notes Wing. Its sustainable features include an exterior constructed from recycled copper and durable brick; rainwater recycling systems that capture water in cisterns for landscape irrigation; automated lighting controls and smart sensors that recognize when people are inside; and energy-efficient motorized windows that take advantage of natural ventilation.
These features can be costly, says Wing, in terms of "first costs," i.e., the price of supply, construction, and installation. "But the real cost of buildings, the much larger cost, is the life-cycle cost," he explains. "What does it take to operate this building over a 50 to 70 year period? Something that may cost an extra $100,000 as a first cost may save a million over the life of the building."
The LEED rating attempts to take into consideration life-cycle costs, thereby reducing a building's operating expenses while also lessening its impact on the environment. However, Wing emphasizes that "LEED is a design tool, not a guarantee of the performance of a building." Critics of LEED certification have called for follow-up performance studies that might result in a building losing certification if it doesn't continue to meet its energy-saving goals.
Wing is optimistic that building efficiency will continue to improve. Near term, he foresees significant advances in glass technology that will reduce a building's energy loss via windows. Further in the future, he predicts less dependence on mega-scale energy grids, and buildings that use energy produced on a neighborhood- or campus-level. Energy delivery may change as well, he says, in a way that enables vehicles and buildings to share a single energy source.
"It's easy to talk cost and numbers, but the greater effects of LEED may be our own enhanced performance within healthy, sustainable architecture. Studies verify the educational benefits for children in schools with substantial natural light and the recuperative effects on healthcare patients of designs that follow LEED and other environmentally-conscious design principles. The measures of success are much more than a simple matter of how high your energy bill is."
Scott Wing, AIA, is associate professor and interim head of the department of Architecture in the School of Architecture and Landscape Architecture. He teaches courses on building materials and construction technology. Wing can be reached at email@example.com.