This study investigates a novel method for controlling the thermal conductivity of soil to enhance the performance of a horizontal ground source heat pump (GSHP). The method calls for irrigation lines to be buried in parallel with the ground pipes for the distribution of water in the area around the pipes thereby contributing to and controlling the soil’s moisture content. The controlled distribution of water within the porous soil promotes heat paths improving the performance of the GSHP system based on the transient seasonal spatial-temporal conditions. A computational fluid dynamics model of the porous soil is developed to simulate the hydro-thermal phenomenon over a short duration (40 hours) during winter conditions. The model is employed to investigate the heat transfer rate between the ground and pipes when the soil’s moisture content is modified and how this affects performance.