This study compares the thermal performance of two novel box-channel PVT collectors, assessing the impactof fins in low temperature operating conditions. This work will contribute the understanding of how PVTcollectors can be integrated with GSHPs for borehole regeneration in cold climates. The two prototype PVTcollectors were tested simultaneously at an outdoor testing facility in Stockholm, Sweden. The outdoor testingenvironment allows for the analysis of a variety of different weather conditions under different fluid flow ratesas well as different roof installations. It was found that the finned PVT collector displayed a potential annualthermal energy output 11% higher than that of the non-finned one at the optimal flow rate of 77 l/h m2. At theoptimal flow rate, fluctuations in wind speed also significantly impacted the observed specific thermal energyof the PVTs, mainly the finned PVT collector, with an increase of 93% being observed due to a 2.5 m/s increasein wind speed.