Sustainability, in general terms, is the ability to maintain balance of a certain process or state in any system. It is now most frequently used in connection with biological and human systems. In an ecological context, sustainability can be defined as the ability of an ecosystem to maintain ecological processes, functions, biodiversity and productivity into the future. [Regional Ecosystem Office (U.S) REO]. Since the 1980s, the idea of sustainable human well-being has become increasingly associated with the integration of economic, social and environmental spheres. Architecture presents a unique challenge in the field of sustainability. Construction projects typically consume large amounts of materials, produce tons of waste, and often involve weighing the preservation of buildings that have historical significance against the desire for the development of newer, more modern designs. Nowadays, architects and designers, should aim at "the creation and responsible management of a healthy built environment based on resource efficient and ecological principles".