This project using waste water heat as a heat source for heat pumps is an Austrian pilot project which aims to explore and to optimize the use of waste heat in the City of Amstetten. The technological heart of the waste water unit is an OCHSNER high efficiency heat pump with a heating capacity of 230 kW. The heat pump uses the energy of the urban waste water as heat source and supplies the entire company building of the Stadtwerke Amstetten as well as the neighbouring power plant with renewable waste water district heat.