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  1. #1

    Drilling for 12 ton geo breaking budget...should I go conventional HP?

    Specs are for a 12 ton Unico heating/cooling system (4 handlers) installed in a 5500 sq. ft. older home about 50 miles N. or Philly. Option one is geo, which brings along a $20-$24k drilling expense. Other option is to use standard heat pumps, saving me the drilling. Equipment and labor save for drilling is pretty much the same for either.

    I'd love to go geo...but I'm wondering what my actual year over year savings would be v. standard heat pump. Is the $24k expense worth the effeciency?

  2. #2
    Join Date
    Aug 2003
    Location
    Lincoln, Nebraska
    Posts
    1,051
    The savings do not usually work out for a Geo when you include the drilling. Payback usually works out to around 20+ years. How efficient are the air to air heat pumps you are looking at?

    Also are you planning on heating hot water with geo?
    Its a good Life!

  3. #3
    Won't get final specs until end of week, so not sure of HP effeciency. What's my target?

    And no, this does not include water heating.

  4. #4
    Join Date
    Aug 2003
    Location
    Lincoln, Nebraska
    Posts
    1,051
    I run them against 16-19 SEER equipment.

    Can youe electric company run a cost comparison for you? They do around here. It would give you a better idea in your area.
    Its a good Life!

  5. #5
    Join Date
    Jan 2007
    Location
    Minneapolis, MN
    Posts
    415
    Have you had an energy analysis done for your home? Improvements to the building shell will lower your heat load and improve comfort.

  6. #6
    Join Date
    Aug 2007
    Location
    WI
    Posts
    1,110
    Skip the Unico if energy savings is a concern. The geo contracter should be able to give you an estimate of savings over the other options. Who decided you need 12 tons? And how did they arrive at that number?

  7. #7
    Due to financial reasons, we have a short window in which to get this job spec'd and in progress.

    Would an energy analysis give me scientific basis on which I could lower the load spec even if the work to the shell is done after the system is installed? Given the size of our home and scope of our projects, it will be months to a couple years until I'll be able to re-seat all casements, seal all infiltrations, etc.

    I'm putting the cart before the horse, I know. That's the situation we're presented with. Is it better to undersize a touch now thinking ahead to the future or design as-is?

    Due to retrofit labor costs, high velocity rises to the top, and Unico is the brand of choice for my distributor. Are other HV manufacturers more efficient, or are you remarking that HV as a whole costs more to operate both with geo and conventional air to air?

    Load calcs were done by our HVAC engineer; calcs I assume are Manual J. I will know for sure this weekend.

  8. #8
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,915
    12 tons of AC is a lot of AC in a reasonably well built 5500 sq ft home that actually has insulation in the walls, and doesn't leak like a barn...

    And when I say that, I mean I would be suspicious of that sizing if the house was in my area of Texas, where our design conditions are for 100Ί outdoor temps...
    If more government is the answer, then it's a really stupid question.

  9. #9
    Join Date
    Jan 2007
    Location
    Minneapolis, MN
    Posts
    415
    An energy analysis will help you understand the house as it is and will be able to guide you to different options through energy modeling. The blower door test will show how leaky the house is and the potential for air sealing. It sounds like you are putting the cart before the horse and you may pay in both comfort and energy costs by doing so.

  10. #10
    Join Date
    Nov 2004
    Location
    NJ
    Posts
    1,204
    Quote Originally Posted by m kilgore View Post
    The savings do not usually work out for a Geo when you include the drilling. Payback usually works out to around 20+ years. How efficient are the air to air heat pumps you are looking at?

    Also are you planning on heating hot water with geo?
    What are your elec rates? Payback for what we pay in my area ($.16) does work out. I know a few guys who are from Nebraska and if I recall correctly they are paying <.$04 though their local co op. At that price I'd agree it's not worth the money.

    EasternPa, your contractor should be able to show you whether or not it is cost effective for your area. Is the proposed system water to water geo with hot / chilled water coils?
    Ed J

  11. #11
    I'll get specs tonight or tomorrow to review, so I can be more specific.

    I've decided to try to get an energy analysis done before we ink...anyone know of anyone that could do this in mid-eastern PA?

  12. #12
    Oh...and rates here are locked at about $0.08 kw/hr, but will bump to 11 in 2010 (rates are currently capped per deregulation). Still cheap for a metropolitan area IMHO.

    Then again, I work for the utility...

  13. #13
    Join Date
    Feb 2005
    Location
    small island in the Pacific Ocean
    Posts
    558
    as mentioned, 12 tons sounds like alot and also with than much capacity get it heating your domestic hot water.

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