Energy Impacts

The construction and operation of buildings requires more energy than any other human activity. The International Energy Agency (IEA) estimated in 2006 that buildings used 40% of primary energy consumed globally, accounting for roughly a quarter of the world's greenhouse gas emissions. Commercial buildings comprise one-third of this total. Urbanization trends in developing countries are accelerating the growth of this sector relative to residential buildings, according to the World Business Council on Sustainable Development (WBCSD). Reducing these emissions is therefore a cornerstone intention and responsibility of green building standards and initiatives.

However, energy savings from green buildings remains one of the most important and controversial facets of LEED's environmental benefits.

LEED requires a minimum of 14% energy savings when compared to the American Society of Heating Refrigerating and Air Conditioning Engineers (ASHRAE) commercial energy efficiency standard 90.1-2001 to 2004. Last year, a New Buildings Institute (NBI) report, released at Greenbuild 2007 and updated in 2008, found that LEED buildings in various occupancy categories saved 25% to 30% of measured energy compared to average commercial energy consumption figures reported by the U.S. Department of Energy.

However, the NBI report has been criticized on various grounds, some of which, in our opinion, are valid and others less so. A resolution of these issues, which ultimately is one part substantive, one part philosophical and one part unknowable, is beyond the scope of this report.