This paper presents an updated assessment of the technical potential of applying geothermal heat pump (GHP) systems in businesses and homes of the United States. The assessed technical potential includes energy savings, carbon emissions reductions, and consumer energy cost savings. This assessment is based on energy consumption data obtained from the latest survey of the energy consumption of residential and commercial buildings, conducted by the Department of Energy's Energy Information Administration. It uses energy savings data for GHP systems compared with existing conventional HVAC systems, which were obtained from the results of a series of computer simulations. The impacts of various climate and geological conditions, as well as the efficiency and market share of existing conventional HVAC systems, have been taken into account in the assessment.