Net zero energy buildings, equilibrium buildings or carbon neutral cities - depending on location and the reasons for making the calculation, the numbers are run differently. The variety of terms in use indicates that a scientific method is still lacking - which is a problem not just in regard to international communication, but also with respect to planning processes as a response to energy challenges. The clarification and meaning of the most important terms in use is extremely important for their implementation. Since October 2008, a panel of experts from an international energy agency has concerned itself with these topics as part of a project entitled Towards Net Zero Energy Solar Buildings. The objective is to analyse exemplary buildings that are near a zero-energy balance in order to develop methods and tools for the planning, design and operation of such buildings. The results are documented in this publication: In addition to the presentation of selected projects, it is not just architectural showcase projects that are shown - the focus is on relaying knowledge and experience gained by planners and builders. Even if many questions remain unanswered: Project examples that have already been implemented prove on a practical basis that the objective of a zero energy balance is already possible today. Since October 2008, a panel of experts from an international energy agency has concerned itself with various topics as part of a project entitled Towards Net Zero Energy Solar Buildings. In this book, the results are documented. It focuses on relaying knowledge and experience gained by planners and builders.