Average Heat Pump COP for Mid-Atlantic
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  1. #1
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    Average Heat Pump COP for Mid-Atlantic

    So I have 3 years of utility data and I am comparing NatGas vs. Heat Pump.
    I am in mid-Atlantic, Maryland an hour south of Lancaster, PA.
    For Heat Pump, I know that COP varies with outdoor temp.
    However, time of use and temp data unavailable.
    If one was to "guess", what would be a reasonable COP to use in a rough comparision. Currently I am using 3.5

  2. #2
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    I'd say 3:1 is average
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  3. #3
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    So, say 3.1 was correct and I used 3.5, I would be favoring the heat pump?

  4. #4
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    Break it down to cost of btu makes it much easier

  5. #5
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    Quote Originally Posted by wraujr View Post
    So, say 3.1 was correct and I used 3.5, I would be favoring the heat pump?
    COP = Co-Efficient of Performance with 1:1 being a COP of 1 or number of units of output for every unit of input. A COP of 3.5 is a higher level of operating efficiency than a COP of 3.1 (note: 3:1 is not 3.1 but rather 3 units of output for every unit of input). Sometimes there is confusion over the different units of measure. BTUhs are used to measure the output of a HP and KWh for units of energy input. Either measure - BTUs or Kw, can be converted to the other for ease of comparison.

  6. #6
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    Look at your median winter temp. Then use the COP oif what ever brands your considering for that temp.
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  7. #7
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    So if Trane xL16i with AHRI 4385663
    Certificate only has Region IV HSPF Rating Heating: 9.00
    Does this translate to anything?

    ADDED: So i averaged Highs/lows from Nov thru March and got 39.1F

    Where could I get COP for Trane xLi 16 3ton at 39.1F??

  8. #8
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    interesting that you pick the XL16i, as i am a huge trane fan... it happens to be not very good on HSPF

    mchild Quote:
    Originally Posted by wraujr
    So, say 3.1 was correct and I used 3.5, I would be favoring the heat pump?

    COP = Co-Efficient of Performance with 1:1 being a COP of 1 or number of units of output for every unit of input. A COP of 3.5 is a higher level of operating efficiency than a COP of 3.1 (note: 3:1 is not 3.1 but rather 3 units of output for every unit of input). Sometimes there is confusion over the different units of measure. BTUhs are used to measure the output of a HP and KWh for units of energy input. Either measure - BTUs or Kw, can be converted to the other for ease of comparison.
    right, it's not 3.1 as it is 3:1. If you would please follow the AOP rules, not that your input here is insufficient or incorret, only professional members with * are allowed to reply. you have the post count to get pro membership and the * if you would like thanks
    If Guns Kill People, Do Pencils Misspell Words?

    http://www.youtube.com/watch?v=An2a1...eature=related

    Before we work on artificial intelligence why don't we do something about natural stupidity?

  9. #9
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    Quote Originally Posted by beachtech View Post
    interesting that you pick the XL16i, as i am a huge trane fan... it happens to be not very good on HSPF



    right, it's not 3.1 as it is 3:1. If you would please follow the AOP rules, not that your input here is insufficient or incorret, only professional members with * are allowed to reply. you have the post count to get pro membership and the * if you would like thanks
    Pretty sure he isn't in the trade, but is a consumer.
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  10. #10
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    Historical Data

    Installed new xL16i (AC) with XV95 NatGas Furnace at end of 2008.
    At the time had utility bills on file back thru 2007. At time of purchase toyed with dual-fuel. Decided to just stick with staright NG with AC. But wondered if made mistake based on various discussions on this board. Ended up entering utility data in Excel spreadsheet to track how new system saved on gas and electric. After read discussion on HP, added formulas to compare cost of NatGas used vs. what corresponding HP electric cost would be.

    To date, my data shows it has been cheaper to heat my house using NatGas than Heat Pump. The COP is entered in a single cell, so I can change it quickly and see change in graph. Currently using 3.5. To get the graph even for last season, would have to raise COP to 4.

    So my experience is that blanket statements made by some that a HP saves money over NatGas are not good. Just saying.. your mileage may vary.

  11. #11
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    Unfortunately. the 16i is not a stellar heat pump. the 15i is a much better heat pump.
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  12. #12
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    Not really comparing xL16i, comparing using COP of 3.5.
    So any heat pump acheiving 3.5 would compare to NatGas as follows

    Name:  rate_chart.jpg
Views: 253
Size:  19.5 KB

    Notable events, after 2008 NatGas prices dropped.
    In 2010, switched to fixed rate one year Electric contract which made HP closer, but still not better. Only way to even was COP of 4.0

    Point is this is real collected data that shows one thing. It doesn't predict future, etc. But it does show that blanket statements about cost savings and performance aren't good.

  13. #13
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    Quote Originally Posted by wraujr View Post
    Not really comparing xL16i, comparing using COP of 3.5.
    So any heat pump acheiving 3.5 would compare to NatGas as follows

    Name:  rate_chart.jpg
Views: 253
Size:  19.5 KB

    Notable events, after 2008 NatGas prices dropped.
    In 2010, switched to fixed rate one year Electric contract which made HP closer, but still not better. Only way to even was COP of 4.0

    Point is this is real collected data that shows one thing. It doesn't predict future, etc. But it does show that blanket statements about cost savings and performance aren't good.
    An average COP of 3.5 is very high. Assuming a median HSPF of 8.5 the average COP would be more like 2.5.

    What are the details of the data in the graph? Did you meter the equipment separately? How was the total BTU output determined?

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