What sets WaterFurnace geothermal units apart from traditional systems? They aren't subjected to the punishing effects of outdoor weather or fuel combustion, so they last longer than nearly any other heating and cooling system. According to the American Society of Heating, Refrigerating, and Air- Conditioning Engineers, geothermal units have an average equipment life of 25 years while the underground loop system has a rated material life of more than 100 years. Ordinary air conditioners, furnace