What are Geothermal Heat Pumps? Geothermal Heat pumps transfer heat to or from the ground The ground will have a cooler temperature in the summer and a warmer temperature in the winter Therefore you can store heat in the summer and collect heat in the winter This is called using the ground as a heat sink (summer) and heat source (winter) https://s-media-cache-ak0.pinimg.com/originals/d6/9f/8f/d69f8fb06d02da08ecd30226a3836265.jpg