Sustainability is gaining a firm presence within the discipline of architecture in spite of the number of obstacles with which it has been challenged: either confronting detractors, sceptics, and the discredit resulting from the abusive use of the term as a marketing tactic, or dealing with the actual practicalities inherent to its implementation. This heightened environmental consciousness increasingly engrained within the profession is solidly supported by a growing social, political and media interest, which has impelled new regulations and the involvement of new experts like physicists, engineers, and ecologists in the design process. This phenomenon is transforming architectural practice and design techniques, moving the focus from a mechanical perspective of architecture (tectonics, construction, materiality, structure) to a biotechnical approach which attempts to equip the architect with instruments to regard buildings as living structures permanently exchanging energy with their environment. Using the environment as a creative generator for design has prompted the emergence of new aesthetic models in current architectural design. The access to new tools, together with new concerns and ways of thinking, have opened new lines of intervention that seem to affect the profession in a more fundamental way. The focus of this paper is to provide an account of these cultural constructs as experimental aesthetic systems, with the intention of not only clarifying their principles and objectives, but also reflecting on the design techniques associated to them. Ultimately, this paper provides a reflection on the role of aesthetics in sustainable design, and on the critical question: is sustainability finally becoming an intrinsic part of architecture?