Five new residential buildings in Vandœuvres, Switzerland, offer new living spaces in total connection with nature and the surrounding forest park. This green building project relies on local and renewable geothermal energy to heat and cool the buildings. To do so, a geothermal borehole field was planned on site, comprising of a total of 23 borehole heat exchangers, operating in function of the residency’s seasonal needs. In the context of this study, GEOEG analysed the performance of the borehole field by means of a 3D dynamic numerical model over 50 years. The advanced simulations were performed in multiple scenarios; GEOEG iteratively studied the borehole field, as well as the geothermal system complemented by thermal solar panels. The analyses showed that the geothermal borehole field could meet 100 % of the yearly energy needs. Furthermore, for the same amount of yearly energy provision, the system has been optimized by reducing the geothermal borehole length by 1’150 m, leading to a 8% reduction in the investment costs.