In the late 20th century a new concept was added to those included in the compass of both structure and function, the consideration of sustainability, hence sustainable architecture. To satisfy the contemporary ethos a building should be constructed in a manner which is <answer>environment</answer>ally friendly in terms of the production of its materials, its impact upon the natural and built <answer>environment</answer> of its surrounding area and the demands that it makes upon non-sustainable power sources for heating, cooling, water and waste management and lighting.
To what should a building be friendly?
environment