The Earth itself can be used as a renewable source of heating and cooling for buildings. By working with nature and using heat pump technologies, a geothermal system moves energy from underground to the Historic Cathedral Barn, providing heat in the winter and cooling in the summer. In regions with temperature extremes, such as Northern Michigan, geothermal heating and cooling is considered energy efficient and environmentally friendly.

Sixteen loops of underground piping, each 200 feet long, run underneath the garden to the basement of the barn. These plastic pipes are filled with antifreeze, or refrigerant, and are buried below the frost line, where the temperate is a constant 42 to 47 degrees all year long. Inside the Cathedral Barn a heat pump uses the physics of compression and thermodynamics to move heat between the Earth and the barn. While heat pumps do use electricity, there is no direct combustion and so no direct production of emissions linked to pollution, climate change, or other environmental hazards. For every single unit of energy powering this geothermal system, four units of energy to heat or cool the building are generated!