This study assesses the performance of a PVT+GSHP system using four different PVT collectors, each withunique design features, for a multi-family building in Stockholm. Thermal performance coefficients areobtained through outdoor testing of each collector under low-temperature conditions, and incorporated into acomprehensive dynamic system model in TRNSYS. The study varies the design and array size of the PVTcollectors and evaluates their impact on the techno-economic performance of the system, consideringtraditional and undersized borehole fields. Technical performance metrics include annual thermal energyoutput, seasonal performance factor and back-up heater utilization, and economic performance is assessed withtotal life cycle cost (TLCC). The results show that when integrating PVTs with GSHP systems, lower collectorcosts should be prioritized over enhanced thermal performance. Despite the finned designs exhibiting a higherthermal yield (up to 10%) this only improves the seasonal performance factor by 0.6% compared to non-finneddesigns, but can increase TLCC by up to 5.2%