Dr. Jakob energy research GmbH & Co. KG (JER) is a German independent research company. The field of activity covers the consultancy for research, product development, marketing, dissemination as well as education and training. The company was established in 2009 and based in Weinstadt in the south of Germany. Expertise in the fields of district heating/cooling, solar/thermal cooling, co-generation, tri- generation as well as energy-efficient buildings enables to strengthen the development of new methodologies and tools for retrofit design towards energy efficient and sustainable buildings and districts.