The energy use of a ground-source heat pump (GSP) for heating, cooling and hot water in a Central Pennsylvania residence (namely, the author's house) is analyzed, compared to a simulation of electricity and a heating-oil furnace (with electric cooling) for these same energy uses. Energy demands for space conditioning in the house are simulated by building a model of the house using the Transient Energy System Simulation (TNRSYS) tool. Overall, the efficiency gain for the ground-source heat pump compared to electricity is 43% for cooling and 81% for heating. For home heating and hot water, the ground-source heat pump has a 42% efficiency gain over a fuel-oil furnace. The system modeled in this paper has a payback period of between four and five years compared to an all-electric system. The payback period compared to a hybrid system of fuel-oil heat and electric cooling is between two and three years.