Boutiquehotel Stadthalle is an eco-friendly hotel in Vienna supplied by renewable energy and with a lavender roof garden. In 2002, the owner renovated the building and it became the first city hotel with a zero-energy balance.

The hotel heating uses water heated by a 130 m2 solar energy plant. A groundwater heating pump, three wind wheels and photovoltaic plant, covering more than 80 m2, create more energy than the hotel can use.

The filling of toilet flushing tanks and watering of the garden are done through a rainwater collection system. The air-conditioning system is fed by a solar energy plant, and during the summer the building can be cooled by cold groundwater which is pumped through the concrete ceiling. Energy consumption is also reduced through the use of energy-saving LED and lighting systems.

Green vines and the lavender garden insulate the hotel while creating an aesthetically pleasing view. During the harvest season, lavender is collected to create sachets.

In January and February of 2014, in cooperation with the University of Applied Arts, the hotel completely renovated seven guest rooms using upcycling approaches. Firewood was converted into coffee tables, books became nightstands, and newspapers became footrests.

Other sustainable actions and impacts include:

- The hotel opened the 'Green Guest Club' - a loyalty programme which allows regular guests to collect points (e.g. 10 % discount for all guests arriving by train or bicycle)

- People can try out a night in the passive house belonging to the hotel

- Organic breakfast is served in the garden during the summer

- Only hybrid taxis are used for guests

- Strict separation of waste and ongoing training for all staff members

- Cleaning supplies are bio-degradable

As a result, the hotel's sustainability has been awarded the EU Ecolabel which increased its competitiveness.