Maryland 7 series verse 5 series

Discussion in 'Quotes and Proposals' started by josh_barney, Apr 2, 2020.

  1. josh_barney

    josh_barney New Member

    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.

    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.
  2. SShaw

    SShaw Active Member Forum Leader

    Hard to say exactly why the contractors did not recommend the 7 series. I believe Waterfurnace requires extra training before they will let dealers sell the 7 series, so not all dealers can sell the 7. The 7 series isn't available in a split unit, so that could be a factor also.

    For me, the additional cost for the 7 series was around $4K for one unit. The projected savings for the 7 over the 5 was 20% or about $200/year.

    One major benefit of the 7 series is it has substantially more heat output than the same-sized 5 series. A 4T 7 series replaced my heat pump and oil furnace and is supposed to handle the entire heat load for my house. Another benefit of the 7 series it that it runs most of the time on a very low compressor and fan speed, so it provides very even output with very little noise.

    With your three separate systems you would want someone knowledgable to design the loop field and pumping solution. There are decisions to be made about whether to put each pump on a separate loop or all on one loop, and whether to use separate pumps for each unit or a single flow center with a variable speed pump that can handle all three units. Your installers may not have much experience with multiple geo heat pumps. Some of the experts on here should be able to help, given more information on what the dealers are proposing.

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