Don't hire this company!  William's installed a geothermal system that wasn't sufficient to heat my home.  I hired an independent energy audit company that spelled out to them that the system was 3 ton's too small.  They have no guarantee and flat out refuse to remove the system and return my money.   My guess is they have never actually removed a unit when they screwed up!  They just wait for you too sue them and then drag it through the court system while you freeze in the winter.
                        
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