This study demonstrates the importance of proper design of a vertical ground heat exchanger according to weather conditions. Thegeographical change in weather should be considered while designing for ground-source heat pump systems. Therefore, comparisons of a house utilizing a ground-source heat pump with a vertical ground heat exchanger were made to a house located in the town of Milton in Ontario by using simple weather data as well as with comprehensive weather data. Models were created using the transient energy system simulation tool TRNSYS to simulate the different scenarios.