In 1997 the Municipality of the city of Dombóvár signed a contract with Dalkia Energia Zrt. for operating a heating network. The upgrading of the heating network supplying about 2000 homes – transforming the system from black oil to natural gas burning, building up new heat centers and renovating existing ones, achieving loss minimization in the boiler room and pipe network – have brought on favorable changes for the consumers. In addition to reducing the heat energy used, it became possible to apply billing based on actual consumption, which can be planned in advance in case of apartments equipped with cost dividers. As a result of the transformations, the air of the city center became cleaner, and the emissions of nitrogen dioxide and sulfur dioxide decreased considerably.