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This paper examines the possibility of using a double U-tube borehole as a heat exchanger between two independent circuits. One U-tube is linked to a 10 m² unglazed photovoltaic-thermal (PV/T) collector and the other to a water-to-water heat pump. The objective of the paper is to quantify the benefits of this proposed system on the seasonal performance factors (SPF) of a ground-source heat pump system used for space heating and domestic water heating of a house located in a northern climate. Results show that the proposed system provides 7.7% more electricity than an uncoupled system because the PV/T panels are cooled by the heat transfer fluid from the borehole. However, 81 kWh per year of energy is required to pump this fluid. The heat transferred from the PV/T panels to the borehole increases the average inlet temperature to the heat pump by about 1.5°C which translates into better coefficients of performance (COP) for the heat pump. However, the COP is not the best metric and SPFs, which include pumping energy, represent a better performance indicator. It is shown that the global value of the SPF increases from 2.82 to 2.88 when the reference system and the proposed system are compared.