Geothermal HVAC systems use the relatively constant temperature of the earth as a heat exchange medium. During winter, heat from the ground warms the fluid, and this warmth is extracted by a heat pump and transferred indoors. In the summer, the process reverses, A heat pump extracts heat from the home and transfers it to the cooler fluid, which is then dissipated into the ground. Geothermal heating and cooling is highly energy-efficient, although installation costs can be higher due to the ground loop installation. It's an environmentally friendly way to heat and cool your home or business.