Les Fèvres Housing Estate, located in Bussigny, Switzerland, is a new district on a former industrial wasteland, directly on the SBB railway line. The project involves the construction of housing, businesses, and craft shops. For this project, GEOEG investigated the feasibility of turning the pile foundation of one of the buildings into an energy pile foundation. In this context, a full-scale energy pile was realized, and a thermal response test (TRT) was performed to characterize the thermo-physical properties of the ground and the test energy pile. Based on this characterization, the energy pile foundation was designed via 3D time-dependent thermo-hydraulic finite element analyses, with due account of the thermal interactions and pipe configurations characterizing the energy piles.