The fossile energy demand of the built environment has to be reduced enormously as the effects of Global Warming become clear. During the last decades, the main focus of research in Building Services was on reduction of energy consumption of buildings themselves through high insulation to reduce energy loses to the environment. At present no longer it is sufficient to look only at the building itself: the occupant and the energy infrastructure need also be considered too. Building, user and energy infrastructure together are linked strongly with a dominating position for the user. Integration between end-user and building is the ultimate in the intelligent building concept. "Connecting" the end-user to a building is complex. User-connectivity is studied and developed further. To supply the user with energy in a sustainable way the application of renewable energy is essential. Design tools for renewable energy installations are only available on the level of individual installations. There is a need for an Integral Design approach which describes at the conceptual level the process as a chain of activities, which starts with an abstract problem (need for comfort) and which results in a more sustainable solution. The paper discusses an integral approach to reach integration of end-user, building and energy infrastructure. Using an integral design method and its morphological charts as a tool, it is possible to integrate the demands of the users and the necessary (renewable) energy supply through a functional decomposition approach. This maximizes the flexibility of the (renewable) energy infrastructure of the building and built environment.