The Boutiquehotel Stadthalle is the first city hotel with a zero-energy balance. 80 rooms including 38 rooms in the new building which is designed as a passive house and 42 rooms in the original house, a house built at the turn of the century. With 130 square meters of solar panels, 93 square meters photovoltaic panels and a water-heat pump, the hotel which is designed as a passive house, produces the energy that it needs itself. Unique for a city hotel, the drinking water is vitalised with a Grander water revitalisation device. Well water is collected for toilet flushing and garden irrigation. Two electric filling stations are planned in front of the hotel. All 38 rooms in the passive house are only equipped with LED and energy-saving lamps. In terms of environmental friendliness and sustainable tourism in Vienna, this hotel has established itself as a leader.