The U.S. Department of Energy reports that there are more than 4.5 million commercial buildings in the United States, occupying as much as 67 billion square feet of space. These buildings make enormous demands on the supply of materials used for construction and the environment in which they exist:
- Commercial and institutional buildings consume one-sixth of the world’s freshwater supply.
- They consume one-half of all virgin wood harvested.
- These buildings require 36 percent of our country’s total energy use and 65 percent of all electrical consumption.
- Buildings produce 30 percent of all U.S. waste output — approximately 136 million tons annually.
- These buildings are responsible for 30 percent of all greenhouse gas emissions.
These statistics drive the green building and sustainable movements in this country, and both concepts have moved from the “ tree hugger ” image to mainstream design and construction. More and more federal and state agencies are mandating new buildings to incorporate energy-efficient heating and cooling systems; reduction in all forms of waste, both solid and liquid; and environmentally friendly work spaces.