Reducing CO2 emissions by improving energy efficiencyand integrating renewables while offering a high quality ofliving and working in neighborhoods and campuses, is thedeclared aim of the three German case studies described in thispaper. The focus is to assess and analyze the different phasesof an energetic retrofitting: planning, construction and operation.Planning tools using 3D geometry of buildings areapplied to model efficiency scenarios and the potential contributionof local renewable generation. By means of a holisticapproach including all relevant stakeholders, this paperdescribes the current experiences on very low carbon neighborhoodsin Germany.