This work is focused on the planning of rational heating systems for urban areas. District heating is an important option to supply heat to the users in urban areas. The energy, sustainability of such option depends on the annual energy request, the population density and the efficiency in heat production. Among the alternative technologies, geothermal heat pumps play a crucial role. Nevertheless, in densely populated areas, an additional consideration is necessary: the subsurface thermal degradation caused by heat pump installations may affect the performances of surrounding installations. This paper aims to propose a procedure to select which users in an urban area should be connected with a district heating network and which ones should be heated through an alternative technology, in order to reach a globally optimal system from the energy viewpoint. The analysis of potential interferences between heat pumps is here conducted using a thermo-fluid dynamic model of the subsurface. The application to an Italian town is considered as a test case for the procedure. (C) 2012 Elsevier Ltd. All rights reserved.