I just had to replace our entire Geothermal system. Everything above ground was replaced. New 6 ton unit, new water heater and separate storage tank as well as steam humidifier$30K
Ouch! But damn efficient system. MIL has geo out on the farm. I would like to mess with the limits. It's cold in the winter and warm in the summer. It needs auxiliary heat and a huge dehumidifier to make it comfy.