In 1970s the energy crisis triggered a new approach to exploitation of limited energy and material sources. In architecture this meant reduction of energy consumption, use of alternative energy sources and building materials. The ideal solution represented an autonomous house, embodied transformation of linear flow of energy, materials, water, food, etc. into circulation, or more efficient use of most substances in a building. The autonomous houses could have been interpreted as the first example of ecological architecture. The most significant impact on architecture meant use of solar energy. The buildings changed from products (or sculptures) with indifferent relation to environment into objects cooperating with nature. The efforts of ecologically oriented architects in 1980s have been characterized by purifying ideas of enthusiastic inventors from 1970s and by trying to define an appearance of ecological architecture. The results were different according to priorities as: energy efficiency, use of alternative energy sources, alternative building materials, green roofs, sun spaces, etc. The 1990s began with a great interest on environmental issues. The ecological approach to architecture became to be an integral part of the building design; so many important buildings erected in last period have been declared as the ecological architecture.