Geothermal heat pump - replacement costs?

[Michael L.]

I'm looking at a potential purchase of a townhouse with a geothermal heat pump system that is about 17 years old. I am trying to figured out what sort of costs this might incur down the line, especially since it is an older system that might have to be replaced at some point.

From what I can tell, the ground loop should be good for 50+ years, so would I just be on the hook to replace the furnace eventually? A new one looks like it would cost about $2300 + installation, which doesn't seem too bad, but I want to make sure I'm not missing something here. I'd hate to get caught on the wrong end of an unexpected five-figure bill if I can help it.