According to author and architect Jason McLennan, “sustainable design is a design philosophy that seeks to maximize the quality of the built environment, while minimizing or eliminating negative impact to the natural environment.” This is a succinct and valuable definition, one that complements the oft-quoted statement of the U.N.’s Brundtland World Commission on the Environment and Development in 1987, “Our Common Future,” defining sustainable development as meeting “the needs of the present without compromising the ability of future generations to meet their own needs.” Sustainable design is also a major movement in contemporary architecture and engineering practice. Above all, it is about “the way things are used; how they are communicated to the world; and the way they are produced.” Elements of sustainable design practice include:

• High levels of resource efficiency overall, including transportation and energy use in building materials, construction and building operations.
• Energy-efficient building systems.
• Renewable energy use.
• Water conservation and graywater reuse.
• Habitat preservation and restoration.
• Use of natural energies for building heating and cooling.
• Rainwater capture, reuse and recycling.
• Natural stormwater management.
• Use of recycled-content, non-toxic, salvaged and local materials.
• Healthy and productive indoor environments for people.
• Durability of building materials and designs.
• Flexibility for building uses to change over time.
• Access to alternative transit modes. 

Sustainable design considers the big picture: the need to transform global settlement and industrial patterns to be healthier and less wasteful, less impactful on the natural environment. It brings these concerns down to the scale of each building, each site plan, each choice of materials and processes. When successful, sustainable design is often hard to detect. A building just feels right on the site rather than obtrusive; there is abundant daylighting; nature is both within and outside; as a design element, water flows naturally from the building into a bioswale or other natural drainage feature; the building is comfortable without a huge rush of moving air; internal spaces create expansiveness and delight; and the overall effect is beautiful. As many scientists have noted, if the solution to a problem is not “elegant,” it is either incorrect or there is probably a simpler solution waiting to be found.