The "LichtAktiv" house is a building that has been modernized and extended, uses regenerative energy, and in which natural daylight and ventilation are controlled. It forms part of a major European project that addresses living scenarios of the future, the Velux "Model Home 2020" project, and the efficient, resource-saving use of energy. In collaboration with the Internationale Bauausstellung (international construction exhibition, IBA) the company staged a competition for the German "Model Home 2020". Students from the Technical University in Darmstadt were set the task of transforming a house on a 1950s housing estate in Hamburg into a climate-neutral residential home. The design submitted by Katharina Fey won the competition. She called it "...home-grown", thereby referencing the estate's principles of self-sufficiency and independence and adapting them to the expectations of 21st century occupants. But now, it is not just vegetables that are being cultivated but energy too.