Sustainability should not be seen as a FASHION, but an attitude present in all stages of the design process. Solar energy, natural ventilation, surrounding insulation, solar protection, are tools present in almost all of our projects. Conceiving the building as an energetic and environmental system, capable of reacting and capitalizing on available and free environmental factors. The maximization of energy efficiency, combined with good environmental behavior, will lead to a new concept of life, and to an increase in the Building's competitive advantages. The Plans, insofar as they condition the design of future buildings, constitute the first element of application of these principles. We have developed a specific methodology successfully applied in the largest sustainable Plan in Europe, The Ecocentre Masterplan, in Ispra, Italy.