A detailed component-based simulation model of a geothermal heat pump system has been calibrated to monitored data taken from a family housing unit located at Fort Polk, Louisiana. The simulation model represents the housing unit, geothermal heat pump, ground heat exchanger, thermostat, blower, and ground-loop pump. Each of these component models was "tuned" to better match the measured data from the site. These tuned models were then interconnect to form the system model. The system model was then exercised in order to demonatrate its capabilities.