The HEP house in Stenløse is a centre for the elderly which has a very low rate of energy consumption. The building is classified in low-energy class 1, which means that energy use does not exceed 30 kWh/m2 per year. Such a low level has not previously been achieved in a single-storey building of this size in Denmark. The centre for the elderly is centred on a large, high-ceilinged common room surrounded by smaller rooms: kitchen, conservatory, billiards room, computer room, toilets, store, equipment room and administration office. The building is constructed from welded steel plates, and is thereby completely airtight. It is also considerably better insulated than usual, and is equipped with eco-friendly windows. Even though the house is airtight, it has a good indoor climate. Air exchange is operated mechanically via a heat exchanger, which ensures that fresh air is drawn in from outside. The heat in the outgoing air is transferred to the incoming air via the heat exchanger, helping to keep energy consumption low.