Providing energy on a reliable and sustainable basis to improve energy efficiency is one of the most crucial challenges the world is facing today. This symposium will contribute to a vital dialog across the Atlantic about what has been achieved and still has to be done to build a more energy-efficient society. Experts from Europe and the United States will share their experience of the past and ideas for the future. The Joint Research Center of the European Commission will present research and development projects on end-use efficiency. The application of this research in the development of codes of practice and European policies will be discussed. Research on energy efficiency includes technologies such as Solid State Lighting, efficient electric motors and power supplies, or building insulation. The contribution to energy efficiency of one of the most innovative regions in Europe, the state of Baden-Württemberg, located in the German Southwest, will be presented. The focus will be on international collaboration in energy efficiency science and technologies. An interdisciplinary perspective on energy efficiency science and its applications will be given by the Fraunhofer Center for Sustainable Energy Systems (CSE), located in Cambridge, Massachusetts. It is partnered within the Fraunhofer-MIT-Alliance, which brings together Europe's leading research organization and one of America's most renowned universities, combining world-leading experience to tackle today's critical energy questions.