I've received 2 quotes so far for geothermal at my house. last year I had a quote for 150-200k, I have received what I consider substantially more reasonable ones now. With the tax credit, historic tax credit, and a historical property tax credit I should be able to get almost a 50% tax brake. We are in howard county Maryland 4 stories, including basement 5400 sq ft above grade, 2000 below grade. Part of the house is 208 years old the other part is 20 years old. MAIN QUESTION Each contractor says a 7 series is not worth the money for this area even though on here I hear everyone push the 7 series over the 5. Is the reason because of the available zoning that the 7 series has and my house doesnt have various zones from one unit? Each floor level has its own unit sort of. 1st quote is for 3 units. Two 3 ton 5 series split units and 1 4 ton 5 series split unit. drilling costs are 31,000 total cost is 86000$ before tax breaks. 10kw auxillary heat for each one, but we will also be keeping our baseboard water heating system as a emergency backup. desuperheater air filtrations etc are all extras. The owner came out twice to look around. He did not say whether or not he did a manual J but checked out ductwork and said it would be fine and seems to be replacing the existing AC units with the same tonnage geo. 2nd quote is 3 4 ton 5 series split units with 10kw aux heating, desuperheater etc is extra costs. drilling 28500 total cost is 98000 before credits. These guys said they did a manual J and the owner came out a second time to walk the property and it took them a long time to get the proposal together, and they are sending out an electrician tomorrow to look at the place as well. Both jobs would include minimal extra ductwork.