While you may not recoup all of your cost for the geothermal system, you can most certainly expect to attract buyers who are interested in purchasing an energy-efficient home. I sold a home in Upton a few years back that had an $80,000 geothermal system. It definitely paid for itself when the home sold.
in what condition is the house? Due to the condition of the house can you get financing or is a "cash deal" only?
Has the house been priced aggressively by the listing agent? Is there any other issues?
Answers to questions like these can determine what should be your offered price.
In other words you will have to get answers before you decide on your offered price. For me in order to be able to assist you will need more info. I wish you best of luck.