This multi-family dwelling is heated and cooled using geothermal energy, which is supplied by 100 m of REHAU RAUGEO Duo green geothermal probes (= 18 units) with a diameter of 32 mm. The remarkable thing about this project is that the buildings were constructed in the middle of central Budapest, where very little space is available. The probes were therefore drilled and installed beneath the building. On the lower reinforcement layer, REHAU concrete core tempering was installed over an area of approx. 2,300 m². In addition, the pipe grid system with RAUTHERM S pipes was used for the underfloor heating/cooling system. Radiator distribution headers and RAUTITAN pipes were also used.