GreenYour.com

Worldwide, buildings account for about 40 percent of energy use[1] and 21 percent of carbon emissions.[2] In 1999, there were over 4.7 million office buildings in the US, with an additional 170,000 added every year.[3] These buildings represent 36 percent of the nation's total energy use, emitting 30 percent of US greenhouse gas emissions.[4] In many places, especially cities, buildings are responsible for a higher percentage of environmental impacts (about 80 percent of New York City's carbon emissions).[5]

But energy consumption isn't the only concern for building owners. Commercial, residential, and educational buildings alike use a significant portion of fresh water—approximately 20 percent of the total water drawn from fresh sources every day. Reducing this amount by a mere 10 percent would save over 2 trillion gallons of fresh water annually.[6]

Given that buildings have such an enormous impact on carbon emissions and water use, constructing, retrofitting, and maintaining eco-friendly structures that conserve natural resources is vital. The term "green building" is generally used to define buildings that demonstrate superior environmental performance compared to typical buildings in a given region. There are many rating systems used around the world to certify buildings as "green."

North American green building certifications

• Leadership in Energy and Environmental Design (LEED) (developed by the US Green Building Council) is the most widely-used system, especially in the US. The Canada Green Building Council has developed a similar LEED certification system for that country. LEED is a points-based rating system with a four-tier standard (Certified, Silver, Gold, Platinum) that takes into account six categories (Sustainable Sites, Water Efficiency, Energy & Atmosphere, Materials & Resources, Indoor Environmental Quality, Innovation in Design). LEED covers many different building categories: New Construction, Existing Buildings, Commercial Interiors, Core & Shell, Homes, and Neighborhood Development.
• ENERGY STAR for Buildings is another eco-building certification system in the US. A building’s energy efficiency is measured against ENERGY STAR standards on a 1 to 100 scale. Any building that achieves a rating of 75 or higher is eligible to display the ENERGY STAR symbol on the building. Partners that work to improve efficiency by 10, 20, or 30 points can be further recognized as ENERGY STAR Leaders.

International green building certifications

• Building Research Establishment Environmental Assessment Method (BREEAM) (UK)
• High Environmental Quality (HQE) (France)
• Green Star (Australia)
• Comprehensive Assessment System for Building Environmental Efficiency (CASBEE) (Japan)