Due to its high thermal performance, ground source heat pump systems (GSHPs) have been introduced as an alternative to reduce energy consumption of heating and cooling systems. The thermal performance of GSHPs strongly depends on ground temperature and energy demand for heating and cooling during the year. Certainly, increasing the global temperature means warmer ground. On the other hand, the thermal load of a building is influenced by thermal quality of building envelop (TQBE) and also influenced by the ambient air temperature. There is absolutely no doubt that the global temperature has increased during the last century. Over time, the buildings designs are changing. These result in changed thermal load of the buildings, ground temperature, and thereby changed the thermal performance of GSHPs. The objective of current work was to investigate the impact of TQBE under different global warming scenarios on driving energy and construction cost of GSHPs in Vienna. This was achieved by comparing the driving energy of the GSHP as well the required total length of the borehole heat exchanger for different GW scenarios and different TQBE. Under climate conditions of Vienna city study shows that improving the TQBE and increasing ambient air temperature result in reduced driving energy of GSHP. While is it not obvious for the required total borehole depth. Namely, after a certain degree of GW, increasing TQBE might result in increased required borehole depth. (C) 2012 Elsevier Ltd. All rights reserved.