It wasn't too long ago (only 8 years) when those of us in the architectural and construction fields were trying to figure out the definition of "green building."  It seemed everyone, myself included, had very strong opinions, but it it wasn't until the US Green Building Council came along with the LEED rating, that the industry finally had a solid definition.

LEED, which stands for Leadership in Energy & Environmental Design, is a rating system that presents a concise framework defining the gamut of building elements and procedures referred to as "green."  It is organized around five categories -- land, water, energy, materials, and IAQ (or indoor air quality).  In each of the categories, a minimum number of points are required to get a basic LEED rating.  More points allow the building owner to achieve a higher rating -- either silver, gold or platinum.

In the early days, beset with increased upfront costs, only a few owners owners and architects ventured to get a LEED rating.  But time has proven that the initial investment in more energy and water efficient systems can have rapid paybacks. LEED Registrants have steadily grown and are now rapidly accelerating.  Last year, 6% of all new construction was registered for LEED.  This year, new registrants are approaching a whopping 40% of total new construction. Clearly, the era of green building has arrived.

The Langston Brown High School in Virginia, which features giant water catchment tanks (resulting in 23% less potable water use) and sun-shaded windows (which daylight 90% of the entire building) is an example of a LEED silver building.  Though precise energy and water calculations are required to achieve a LEED rating, until now there has not been a performance survey of completed LEED projects.  Just last month, USGBC released a complete report inventorying over 200 LEED buildings for performance in each of the 5 categories.  Finding were as follows:

LAND USE - focusing on reduction of commute distance, LEED buildings have saved 400 million vehicle miles to date.  By 2020, this will be 4 billion vehicle miles.  At an average of 23 miles per gallon of gas, that saves 173 million gallons of gas and approximately 42 million tons of CO2.

WATER USE - low-flow plumbing fixtures, xeriscaping, and and other conservation strategies will result in a projected savings of  245 billion gallons of water.

ENERGY USE -- The average LEED building will save its owner between 25-30% of a energy use over a typical non-LEED building.  Project out to 2020, that is the equivalent of avoiding the combustion of 50 million tons of coal.

MATERIALS USE -- It is estimated that by 2020, over 325 million tons of waste will be diverted from landfills because of LEED buildings.  LEED is also largely responsible for a major upsurge in spending on recycled content materials and products sourced from sustainable materials, $10.5 billion to date.

INDOOR AIR QUALITY -- LEED buildings are better lit and have less toxic compounds, which results in across-the-board increases in occupant productivity.  To date, over 350,000 employees have seen an estimated $120,000,000 in increased productivity.

To learn more about the LEED rating and green building check out the USGBC website.

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