Heat Pump Balance Point Sheet
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  1. #1

    Heat Pump Balance Point Sheet

    I saw an older post on here where someone said they have a heat pump balance point set up on an excel file/program. I was wondering if anyone has this and how well does it work.

  2. #2
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    I can email you what I have, it is an excel file as you said.

    You can check it out and decide for yourself. I do use it occasionally.

  3. #3
    Thank you, I would like to check it out.

  4. #4
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    Quote Originally Posted by arc8 View Post
    I can email you what I have, it is an excel file as you said.

    You can check it out and decide for yourself. I do use it occasionally.
    Would you please send me one as well? Do I need to post my email or send it too you?

    rich

  5. #5
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    At the risk of sounding ignorant I have to ask what is a heat pump balance point? I've been in the business for over 20 years and have never heard of a heat pump balance point>

  6. #6
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    SouthEast NC ICW & Piedmont Foothills
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    can only assume it is the point at which a particular heat pump can no longer produce enough heat for a particular structure based on outdoor temp........................if that is what is being referred to..........

    that point will changed based on every brand, mod, structure.....one would have to be very intimate with the engineering numbers for every piece of equipment produced and the structure it is trying to condition
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  7. #7
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    Quote Originally Posted by welling service View Post
    At the risk of sounding ignorant I have to ask what is a heat pump balance point? I've been in the business for over 20 years and have never heard of a heat pump balance point>
    1st. Thanks for sending me the Excel sheet, Arc,

    Now to this current question.

    Heat Pumps and Air Conditioners capacity changes with environmental conditions outside AND inside. As the temperatures outside drops or rises so does the amount of BTU's the home needs to be added or removed depending on which operation your in, heating or cooling.

    The Heat Pump or Air Conditioners fan and compressor are constant in terms of piston displacement and fan CFM. So, if you change the outside temperature the fan continues to move the same amount of air and thus if the temperature is colder outside in heating the amount of heat absorbed is reduced. A 4 ton heat pump in heating may see more than 75% reduction in capacity when temperatures drop from 65 outside to zero.

    If we know the btu requirements of the home at zero and at 65 you can plot a line. Then if we know the capacity of the heat pump at 65, 45 and 17 (info that manufactures provide) we can plot a line as well. The lines will look like an X , where they cross is where the balance point is, theoretically that is under perfect conditions. So where the X balance point is we can then determine what the minimum back up heat should be to make up the difference that the heat pump would not be able to produce after reaching the balance point. Our company always allow for a backup heat to maintain a 70 degree home, but to reduce huge temp swings and higher demand loads if the contractor can pick a heater with stages and get the first stage to meet as close as possible to the lacking heat output of the heat pump then the comfort and costs will be reduced slightly.

    Now, there is also an economic balance point, which we have found not to be much of an issue since the higher rated units are here. When we were dealing with 7 Seer units it was possible that the heat pump would cost more to run than its BTU output. Now we can run them down to zero under certain conditions and let the heaters supplement. However in some areas they turn them off in the 30's based upon the degree days in their area and humidity factors. Our systems in Ohio are much different than lets say the Dakota's, or even better yet Arkansas. Two stage or Dual stage units are changing this rule as well. But if you look at the numbers a 3 ton verses a 4 ton heat pump may have 5,000 btu's output difference at 17 degree outside temperatures. This isn't much but when you run the cost numbers it may be significant in terms of utility costs. Computers have made it more simpler to figure these things out but I like knowing whats going on, it simplifies in servicing the product.

    I'm my own home I turn it off my heat pump at 34 degree's, the amount of money saved verses normal wear on the compressor is my reasoning, besides, our area does not have a demand meter and my backup is natural gas. If gas goes down further in costs for us I will not use my heat pump. If there isn't much cost savings I always have believed not to cause the compressor to wear out sooner with normal usage and switch to the backup, but I usually ask my customer. We get well over 20 years on our heat pumps with the way we've done things..

  8. #8
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    arc8

    Again, thanks for the excel file.
    I just played with it, this thing has an economic balance point too, very nice!

    I have noticed that the load starts at 55 instead of 65. We have always been taught to start our lines at 65 degrees. Starting at 55 would shift the lines to a lower balance point, so those who are use to the 65 should be aware of this fact. I'm going into it and see if its changeable.

    Thanks again

    Rich

  9. #9
    Thank you arc8 for sending it to me.

  10. #10
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    Quote Originally Posted by Rich View Post
    Would you please send me one as well? Do I need to post my email or send it too you?

    rich
    I've seen your email in your profiles, did you get it?

  11. #11
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    Quote Originally Posted by arc8 View Post
    I've seen your email in your profiles, did you get it?
    I've notice you did get the file.

    What would be nice is if I could get in the program (unlock it) and did some modifications to it... anyone!

  12. #12
    Join Date
    Aug 2000
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    Sandusky Ohio
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    Quote Originally Posted by arc8 View Post
    I've notice you did get the file.

    What would be nice is if I could get in the program (unlock it) and did some modifications to it... anyone!
    Yes I did receive it. I fooled around with it for a few minutes and will try to break into it the upcoming week.

    I mentioned that it starts at 55 instead of 65, but I noticed the lines could be extended, so maybe the calcs are really for 65 and nothing for me needs to be changed. I will put some known values in from ARI and see if they match up with the 55 or the 65 O.D. temperature ratings.

    I'll report back when I get too it.

    This is really a cool program, just last week I made up comparison charts on about 12 pages with different equipment and heater values for their balance points and this is SO EASY compared to that!

    Thanks again arc8

  13. #13
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    Tahlequah OK
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    Thanks Rich for the education. ARC 8 may I have a copy of the the balance point sheet? You should find my email on my profile. Thanks

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