The grounds of the Vitos health centre in Marburg, near Frankfurt, are dotted with mature trees and historic buildings from the late 19th century, which have served as a psychiatric clinic for 140 years. At the northern edge of the open grounds, the city of Marburg has ­established one of the first children’s day-care centres in Germany to achieve the plus energy standard Effizienz­haus Plus (Efficiency House Plus). The building is expected to achieve an annual energy surplus both in terms of final ­energy and primary energy.