The age of positive energy buildings has come

For quite a long time, experts considered zero energy buildings or buildings that do not require a heating system (as the passive house was inappropriately described at the begin) to be landmarks in this development process. The vision of a building that produces more energy than it uses for running the technical building systems (and thus becomes an energy-generating unit itself) once belonged to a distant, perhaps even unattainable future. Undoubtedly, the development of the surplus energy house marks another quantum leap in the field of energy research to which Fraunhofer IBP research staff contributed their share, proving great commitment and initiative. In the meantime, IBP's Heat Technology team has extended its scope, now providing surplus energy building concepts not only for various residential buildings, school buildings and other educational buildings, but also for office buildings and even for existing buildings. Each of the 250 exciting pilot building projects the Heat Technology team has realized so far has taken the development a step further. Buildings functioning as energy providers create a scenario that opens up completely new ways of securing the energy supply. To ensure sustainable success, it takes both: detailed, fully developed concepts of building types and excellent quality of building construction. Equipped with these parameters, energy solutions for districts or even for entire cities can be tackled. Pilot projects need strong partners who pull together to ensure that such pilot schemes will have the necessary effectiveness. When it comes to setting and supporting sustainable trends in society, the challenge for policy is to initiate demonstration projects, to provide start-up financing, and to create the appropriate framework for change. The high relevance of these research projects is confirmed by the fact that emerging superior trends need to be analysed in the course of the project, that guiding principles have to be derived from these analyses, and that experience gained from the project has to be summarized in guidelines, for instance. The paper presents experiences made at various surplus energy buildings based on detailed measurement concept, which enables the IBP researchers to evaluate the design results obtained for different building concepts. The measurement configuration allows establishing a comprehensive balance of energy flows on a monthly basis, thus visualizing the performance of the installed plant components. In this way, users will keep informed on the current status of their energy balances. Besides, the air temperatures and CO2-levels measured in relevant spaces (like living rooms or bedrooms) are continuously recorded