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  1. #1
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    American Standard Heat Pump COP's

    I am a home owner with a recently installed dual fuel (natural gas and heat pump) system. I have a thermostat that allows me to adjust the balance point. As the weather has been getting cooler here in Pittsburgh I have been exploring but have not yet found the limits of the heat pump. So far I have not had any problem with the heat pump maintaining the set temperature or complaints relative to blowing cool air. When I contracted for the system, high gas prices made it obvious that using the heat pump to the limits of its ability to heat the house would be most economical. A recent drop in the gas price, however, has given me the incentive to accurately calculate the economic balance point. From reading some of the threads on this forum I understand how this is done but I find that I am unable to locate COP data for my heat pump installation. It does not seem to be available from the American Standard web site. This is my equipment:

    Heat pump: Heritage 14, 2 1/2 ton, 4A6H4030B1000AA
    Indoor Coil: 4TXCB031BC3HCAA
    Furnace: Freedom 95, Comfort-R, AUH2B080A9V3VA
    Thermostat: ACONT803AS32DAA

    I did find COP data for a comparable Goodman heat pump. If I cannot get actual manufacturer's data from American Standard will I be pretty close if I use the Goodman COP data? Perhaps I should reduce the Goodman COP figures by about 7% since I figure that my HSPF with this coil is only about 7.9 while the Goodman heat pump probably is about 8.5. The Goodman model that I used is a 2 1/2 ton unit, model SSZ140301A.

    I have enjoyed reading many of the threads on this forum and appreciate the good information that you have freely given. I thank you for any help that you can give me on these questions.
    Last edited by Calum; 10-23-2008 at 04:42 PM.

  2. #2
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    You can try and contact American Standard directly or the installation contractor. You are looking for either the "Product Specifications" or "Technical Specifications" for the heat pump condenser.

    Good luck.

  3. #3
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    These number are for Trane but should be close. The columns are outdoor temp, BTU output, and Kw used at 70 indoor temp. I assume you can calculate the COP.

    2--11.6--2.36
    7--13.3--2.38
    12--15.0--2.41
    17--16.7--2.43
    22--18.0--2.42
    27--19.3--2.42
    32--20.5--2.41
    37--21.8--2.41
    42--23.1--2.40

  4. #4
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    Quote Originally Posted by mchild View Post
    These number are for Trane but should be close. The columns are outdoor temp, BTU output, and Kw used at 70 indoor temp. I assume you can calculate the COP.


    2--11.6--2.36
    7--13.3--2.38
    12--15.0--2.41
    17--16.7--2.43
    22--18.0--2.42
    27--19.3--2.42
    32--20.5--2.41
    37--21.8--2.41
    42--23.1--2.40
    These numbers don't jive. The btu output goes from 11,600 to 23,100 and the kw's hardly change. Not right.

  5. #5
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    Quote Originally Posted by gary_g View Post
    These numbers don't jive. The btu output goes from 11,600 to 23,100 and the kw's hardly change. Not right.
    Your are correct that the Kw figures are not correct (they were for 80 indoor temp), but the correct numbers are not much different:

    2 11.6--2.25
    7 13.3--2.27
    12 15.0--2.29
    17 16.7--2.31
    22 18.0--2.30
    27 19.3--2.30
    32 20.5--2.29
    37 21.8--2.29
    42 23.1--2.28


    And just to make sure that Trane (A/S) isn't the only manufacturer that has this kind of performance here is the data for a Carrier 38QRR (70* indoor temp):


    -3--11.11--2.20
    7--14.19--2.20
    17--17.40--2.20
    27--20.82--2.20
    37--24.44--2.20
    47--28.60--2.23

  6. #6
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    OK - maybe it's just me. I was expecting more of a range of kw's between high and low temps.

    For Goodman's 2 1/2 ton R22 heat pump, at 70F indoor temp:

    T------Mbtu-----KW

    0------11.2------1.8
    5------12.9------1.85
    10-----14.5------1.89
    15-----16.2------1.93
    20-----17.8------1.98
    25-----19.3------2.02
    30-----20.9------2.06
    35-----22.9------2.00
    40-----24.8------2.04
    45-----26.7------2.08

    Take care

  7. #7
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    Quote Originally Posted by mchild View Post
    Your are correct that the Kw figures are not correct (they were for 80 indoor temp), but the correct numbers are not much different:
    -----------------C.O.P
    2 11.6--2.25----1.51
    7 13.3--2.27 ---1.72
    12 15.0--2.29---1.92
    17 16.7--2.31---2.12
    22 18.0--2.30---2.29
    27 19.3--2.30---2.45
    32 20.5--2.29---2.62
    37 21.8--2.29---2.78
    42 23.1--2.28---2.96

    I added the C.O.P. column.

  8. #8
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    2 11.6--2.25 = COP 1.51
    7 13.3--2.27 = COP 1.72
    12 15.0--2.29 = COP 1.92
    17 16.7--2.31 = COP 2.12
    22 18.0--2.30 = COP 2.29
    27 19.3--2.30 = COP 2.46
    32 20.5--2.29 = COP 2.62
    37 21.8--2.29 = COP 2.79
    42 23.1--2.28 = COP 2.97

    Not bad.
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  9. #9
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    Quote Originally Posted by beenthere View Post
    2 11.6--2.25 = COP 1.51
    7 13.3--2.27 = COP 1.72
    12 15.0--2.29 = COP 1.92
    17 16.7--2.31 = COP 2.12
    22 18.0--2.30 = COP 2.29
    27 19.3--2.30 = COP 2.46
    32 20.5--2.29 = COP 2.62
    37 21.8--2.29 = COP 2.79
    42 23.1--2.28 = COP 2.97

    Not bad.
    I very much appreciate the help with this. Using these figures does actually impact where I will set my balance point. The economic balance point at my current gas and electric rates appears to be 37 degrees. I have signed on to a utility purchasing program which when it kicks in should lower my electric rates enough that the economic balance point will be 22 degrees. Natural gas rates in my area change every three months so I will have to monitor these and compensate accordingly. I must confess that I was a little disappointed by the actual COP's for this unit when compared to the Goodman unit COP's that I had previously looked at. For example, at 32 degrees the COP for the Goodman unit would be above 3.1 compared to 2.62 for this unit.

    With your forbearance I will ask a few more questions:

    1. Beenthere, Can you confirm that these figures are for the Trane equivalent of my actual heat pump?
    2. Does the shortfall in COP when compared to the Goodman heat pump make sense?
    3. Are the Trane/American Standard figures actually still a pretty good performance?
    4. At what outdoor temperature would the effect of defrost cycles become a factor in setting the balance point?

    In asking these additional questions, I do feel like I may be taking advantage of you, so please feel free to decline to answer any or all of them! Thanks again for the help that you have already given me.

  10. #10
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    For reference only, my 2-ton Trane heat pump has a COP of 3.42 @ 42F OD temp and 70F indoor temp. The Goodman you referenced is around 3.55 at the same condition. You're sitting at a COP of 2.95 at that point, if the data provided is for your units.

    The problem I see is that you're comparing the performance of heat pumps and thier very well matched variable speed air handlers against your indoor coil and furnace blower. I'm no expert, but I don't think a seperate coil/furnace blower setup can match the efficiency of a perfectly matched air handler. From the AS/Trane websites, it doesn't look like that coil is truely designed for heating, so I'm sure that's affecting performance.

  11. #11
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    I don't have access to Trane extended performance charts.
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  12. #12
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    So Sorry. I should have addressed that question to mchild.

  13. #13
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    Quote Originally Posted by cacasesi View Post
    For reference only, my 2-ton Trane heat pump has a COP of 3.42 @ 42F OD temp and 70F indoor temp. The Goodman you referenced is around 3.55 at the same condition. You're sitting at a COP of 2.95 at that point, if the data provided is for your units.

    The problem I see is that you're comparing the performance of heat pumps and thier very well matched variable speed air handlers against your indoor coil and furnace blower. I'm no expert, but I don't think a seperate coil/furnace blower setup can match the efficiency of a perfectly matched air handler. From the AS/Trane websites, it doesn't look like that coil is truely designed for heating, so I'm sure that's affecting performance.
    Outstanding points.

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