We're Hilliard's Primary Geothermal Contractor! Hilliard, Ohio, homeowners have all sorts of reasons for desiring a geothermal heating and cooling system: phenomenal year-round comfort – no matter how extreme the weather variations smooth operating efficiency energy efficiency (They would look forever to find a more "green," more natural way to heat and cool their homes!) significant – often outstanding – savings on their energy bills superior installation and maintenance from Geo Source One Inc., Hilliard's geothermal experts. Learn more about what a geothermal heating and cooling system can do to improve your family's comfort. Check out our Geothermal Savings Calculator. Then contact Geo Source One Inc.. We sell, install, and service WaterFurnace geothermal systems, the very best available today.