I've got a 13-year-old ClimateMaster Ultra Classic geothermal unit. Recently during the "polar vortex" the blower motor went out. After replacing that, the system still did not work properly so my HVAC guy checked the refrigerant levels and found one compressor very low but the other one low but still able to run. Turns out there was a leak in the coil. We have cost estimates on replacing just the coil and on putting in a whole new system. After tax credit for a new system, it would end up being a bit more than 3 times the cost of just replacing the coil. We plan to stay in this house for at least 10 years. Our HVAC person said these units usually last 10-15 years, so based on that I would definitely replace. On the other hand, things I've seen on-line say the life of a geothermal unit should be 20-25 years. If so, this unit might go another 10 years or so. I'd appreciate your thoughts about this.