Replacing propane systems with a Geothermal Heat Pump has been a huge part of our business. The payback for a geothermal system when compared to the cost of propane is generally 2 years or less! The 30% Federal tax credit has helped homeowners even more. Homeowners receive a tax credit equal to 30% of the complete system install cost (with no cap). This along with the Idaho Power Incentive check ($1,000 written directly to the owners) basically cuts the cost of a system in half! We installed an underground drain field on this system as well.