The ground source heat pump (GSHP) and variable refrigerant flow (VRF) systems are the most competitive HVAC technologies in the current market. However, there are very few studies reporting the comparison of the annual energy consumptions and Electric Peak demand reductions between GSHP and VRF systems because of the limitation of the whole building energy simulation software. Current version of EnergyPlus can model both GSHP and air-source VRF. Therefore, three representative US climate zones including Chicago, Baltimore and Atlanta are selected for conducting this comparison study. The EnergyPlus simulation results show that the GSHP system not only saves more energy than the air-source VRF system but also significantly reduces the Electric Peak demand regardless the climate conditions. This makes the GSHP system a more desirable energy efficient HVAC technology for the utility companies and their clients. (c) 2014 Elsevier B.V. All rights reserved.