Villa F / the off-the-grid house in the central highlands of Germany The client of the „off-the-grid house“ in the central highlands of Germany, called Sauerland, has an agricultural background. However, he is more than typical farmer. Together with his father, he is a pioneer of the biogas-technology in Germany. Energy-efficiency and protection of the environment are the main elements of the design. The supply and disposal of the building is due to the biogas system self-sufficiently - therefore „off-the-grid“. Meanwhile, through the exemplary ecological nature of this building, the whole village decided to connect to the local-heating-grid of the farm. One day, the client walked into our office and said, „I would like to have a round house“. Well, a round house is rather unusual, but that was the exact reason to take on this challenge. The main reason for him was that, from an energy efficient point of view, the surface/volume proportion should be ideal. However, since it’s rather hard to live in a sphere, the client went for a cylindrical shape.