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  1. #1
    Hi all -

    I'm replacing my 16 year old heat (80%) & a/c (11 seer), and one option I'm considering is a heat pump. Do anyone have any positive & negative comments on heat pumps? I live in the KC area, and it's below 30 degrees 20% of the winter, so from my understanding, the backup (80%) gas heater will run 20% of the time. For heat pump owners - my utility company gives over a 50% discount on electric rates for 8 months of the year. I'm trying to decide if the higher cost of electric heat pump in winter and the lower utility rate 8 months of the year will offset the much higher gas prices (if I went with traditional split units) we've all seen in the last 3-4 years.
    Is there a website where I might be able to plug in some numbers (temp, util. cost, furnace & a/c energy rating) to determine which system is best for my climate?

    Thanks again

  2. #2
    Join Date
    Jan 2005
    Location
    Emerald Coast
    Posts
    936

    Talking

    Try this one out- http://www.hvacopcost.com/

  3. #3
    Join Date
    Apr 2004
    Posts
    7,680
    Your understanding is incorrect.

    First off I doubtr its below 30 20% of the time but even assuming that, the heat pump still does the work, the auxiliary electric heat only supliments the heat pump. For instance, if its say 25 and your heat loss is 30,000 at that condition. If you had a 2.5 ton system which would produce 30,000 if it were 47 degrees might put out say 22,000 btuhs at 25. You would need only to suppliment it with the shortfall of 8,000 btuhs.

    You should be able to have a good contractor run the real numbers for you. Odds are you will find a savings even if the utility didnt offer the discount. With the discount, you will save significantly over your current set up even if you bought another 11 seer system. The trick in your case is making sure the ductwork is designed properly to prevent noisy or drafty operation.

  4. #4
    Join Date
    Jan 2002
    Location
    East Grand Forks, MN
    Posts
    1,373
    Is there a website where I might be able to plug in some numbers (temp, util. cost, furnace & a/c energy rating) to determine which system is best for my climate?

    I dunno about website numbers, but your last statement is wrong thinking. to determine which system is best for your house is basically determined by your house! and your utility rates, of course.

    there's nothing wrong or bad about heatpumps, matter of fact, heatpumps run and heat real well up here in the North country.

    Numbers, ask your contractors, if they can't or won't help you, stay away from them. Why, because they probably won't or can't do a load calculation.
    Your utility companies can also help you with your energy cost as well.

    Summary:
    Your House will determine if a heat pump is worth considering installing with a good payback.

    GL

  5. #5
    Join Date
    Feb 2005
    Location
    Dothan, Al
    Posts
    3,453

    benny

    A heat pump only saves money on heating cycle. How much you save is dependent upon how much heat u use.

    Heat pumps have more parts than conventional a/c w/electric heat. Generally, the heat pump will result in more & higher repair bills throughout its life. Also, generally, the life of the heat pump will not be as long as the a/c w/electric heat.

    Richard

  6. #6
    Join Date
    Apr 2004
    Posts
    7,680
    Why would he pay full electric rates AND pay for 1/3 the efficiency for at least 85% of the time for 8 months just to avoid a reversing valve and defrost board? Currently, if I understand him correctly, he has an 80% gas furnace which has far more parts, if you buy into that more parts more failure stuff.


    Benny, you want to pay close attention to not only the SEER but you need to consider the HSPF which is the heating efficiency of the heat pump. Many systems are designed to achieve higher SEER because that is the standard while disregarding the heating efficiency. Unfortunately, pushing SEER in a good heat pump market like yours where heat is more than half the running time may be somewhat deceptive.

  7. #7
    Thanks everyone for the help. The unit I'm consider if I go with a heat pump is the Trane XR12 (12 SEER) w/ a Trane XR80 (80%) furnace. The other option is a Lennox G50 furnace (80%) and Lennox HP25 heat pump (13.05 SEER).

    The backup heat is gas, not electric, and the utility company rate goes from 6.51 cents p/kwh to 3.39 cents per/kwh for heat pump owners 8 months of the year. Even if I installed the heat pump and did not use it (used the 80% furnace) I would save about $250 for the 8 months in reduced electric rate and recoup the heat pump cost in less than 4 years. My gas bill would probably go down some because I'm replacing a 16 year old 80% furnace with a new 80% furnace. Just my thoughts.

  8. #8
    Join Date
    Jun 2004
    Posts
    146
    If your electric rate drops to 3.39cent/KWH, you should forget about the gas furnace and go with electric backup. On the really cold days when the heat pump alone isn't enough, the heat pump/heat strip combo will be much cheaper to operate than gas backup. At 3.39cent/KWH, even straight electric resistance heat will be cheaper than gas heat.

  9. #9
    Join Date
    Nov 2004
    Posts
    2,927
    Originally posted by bennyfranklin

    Is there a website where I might be able to plug in some numbers (temp, util. cost, furnace & a/c energy rating) to determine which system is best for my climate?

    Thanks again
    Someone asked a question like this yesterday,and the answer was:
    http://www.johnmills.net/work/advice.html
    http://hphaa.com/services/installation/installation.htm
    http://toad.net/~jsmeenen/phrase.html
    http://www.proctoreng.com/articles/bigger.html

    I hope these help

  10. #10
    Join Date
    Nov 2004
    Posts
    2,927
    ...but I didnt see a calculator at those sites.I should have checked first.
    Oh well.

  11. #11
    Originally posted by go_redskins
    If your electric rate drops to 3.39cent/KWH, you should forget about the gas furnace and go with electric backup. On the really cold days when the heat pump alone isn't enough, the heat pump/heat strip combo will be much cheaper to operate than gas backup. At 3.39cent/KWH, even straight electric resistance heat will be cheaper than gas heat.
    My thought was to have both gas & electric because if gas prices goes down from its high prices of the last few years, it may be cheaper to use gas once again. In my area, my gas bill went from approx $100 to $250 for the same monthly usage over the last three years. Additionally, electric may go up. I can't predict what will happen in 5 or ten years, but would prefer to have gas & electic heat available in my home since heating is about 75% of my yearly utility dollars. I do agree with your point about the heat strip w/the lower rate. Just can't predict future prices.

  12. #12
    Join Date
    Jun 2004
    Posts
    146
    There is no way to predict the future. But you can place bets (and by choosing gas or electric backup, you are making a bet).

    When it gets cold enough to cause auxiliary heat to be needed, with electric backup, the weighted average COP of your heat pump/heat strip combination will be somewhere around 1.5 to 2.0. At 3.39 cent/KWH, a dollar of electricity will buy you between 151K and 201K BTU's.

    At a dollar per therm of natural gas, an 80% gas furnace will provide just 80K BTU's per dollar.

    So in the near term, the gas backup will be more than twice as expensive as electric backup. In the long term, the only way you'd win with gas backup is if electric rates go up so much faster than natural gas rates that it offsets all the years of savings you had with electric backup. That's not a bet I would make. In the long term, electric rates will be more stable than natural gas because it's generated from multiple sources and will be generated by the cheapest means available.

    BTW, I'm the Seattle area where the climate is ideal for heat pumps. My gas rate is about $1.00/therm and my electric rate is $0.08/KWH. I use to have a 80% gas furnace. I was paying over $200/month during the winter months for heating. I removed it and replaced it with a heat pump and heat strip backup. My last winters heating bills dropped to less than $100/month.

  13. #13
    go_redskins - thanks for all the helpful insight. You are going to coax me into an all-electric house if I'm not careful. How 'bout some water heater stats (electric vs gas)

    Hmmm, and what to do with the vent-free gas space heater in the basement.

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