Improving sustainability and the environmental performance of buildings is an important mission. Commercial and residential buildings account for about 40% of primary energy consumption nationwide. Conventional construction consumes a large amount of raw materials and creates a large waste stream. Once completed, buildings also have a considerable impact on human health and the environment. The growth of "Green" building practices is a direct response to these findings. The US EPA defines Green Building as:
The practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life cycle, from siting to design, construction, operation, maintenance, renovation, and deconstruction. This practice expands and complements the classical building design concerns of economy, utility, durability, and comfort. Green building is also known as sustainable or high performance building.
Green building rating systems were developed to define and evaluate these practices. The first and most widely used rating system in the US is Leadership in Energy and Environmental Design (LEED), developed by the US Green Building Council (USGBC). Two other existing systems are Green Globes, developed by the Green Building Initiative, and the Living Building Challenge, developed by the International Living Building Institute. There are similar green rating systems in use in more than 25 countries. The rating systems are organized using point totals addressing several categories of environmental, health, and energy conservation practices.
