Doubt their claims

We had geothermal before we down-sized. It is virtually impossible to have a “zero” electric bill from geothermal alone because the system requires electricity to run the pumps and blowers. Our typical winter electric bill for a 4,000 sf Home was $200; still a bargain but not free. Ask for a 12 month utility bill history; your realtor should be able to get.

One other comment. Geothermal heat never “feels warm”. You won’t stand on the heating vent to feel the heat. It’s a very gradual warmup unless you use the emergency electric heat, which defeats the purpose. My wife found it impossible to feel warm enough.

I would buy a home with geo again, but I wouldn’t spend the upfront money to install a system.