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  1. #1
    Join Date
    Jun 2008
    Posts
    58

    Heat pump advice

    Quick question for you guys. Trying to finally button up this install

    Were building a tight house with spray foam insulation in the St. Louis area, Were split pretty even with the heating and cooling days but the nod probabbly goes to having the heat on more than the AC but not buy much. Here is my question. I have used various calculators and according the price of electric and NG

    .10 kwh vs 1.14 therm. When I use the Calcs they give the nod to the heat pump but not buy much only 10-15$ a month.

    So here is my question and my rational maybe its flawed but that is why I have you guys.

    I don't see NG coming down in price althought the Gas company told me they drop the price in the winter to around .80 then the nod goes to the Gas/AC system then. (Don't know if its going to happen or not)

    I figured that since this is a tight house and it is going to have an efficient system 16 seer or better either way, and the cost is about the same for either system.

    The Heatpump might be the way to go since its a 2 stage system the unit should only have to run on low for a little bit of time in those moderate days were as the gas furnace is going to fire up to 60-80%. in theory the HP should save me some money. When the weather is freezing out its a wash since both furnaces are close on specs 94% vs 95%

    I don't know I need some advice thanks for the help.

    99% of the homes here are standard gas and AC

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,901
    Personally I would think HP would be much cheaper heat. With temps in the 30s out, a GOOD heat pump would cost about $8.88 for a million BTUs put in the house. A 95% gas furnace would be $12.00 according to the calculations. If nothing else, at least consider dual fuel.

    Don't oversize. Make sure whomever sizes the equipment understands tight homes. A friend of mine is a foamer and he's seen what happens when HVAC dealers don't know what they are doing and put in too big of an A/C. 2 stage equipment can help but check how well they dehumidify, especially on low stage. And you might want to plan on a whole house dehumidifier. Another friend with a foamed house had to do that to keep the house dry when the A/C wasn't running. And he has a 2 stage 50/100% staging heat pump.

  3. #3
    Join Date
    Jul 2008
    Location
    Jefferson, GA
    Posts
    46
    Why not go dual fuel?

  4. #4
    Join Date
    Jul 2008
    Posts
    53
    I would say dual fuel would be the way to go.

  5. #5
    Join Date
    Jun 2008
    Posts
    58
    I must appologize, I am going to go duel fuel if I go heat pump

  6. #6
    Join Date
    Jun 2008
    Posts
    80
    I agree with BaldLoonie. My numbers show $12/Million BTU for NG Furnace 95% efficient.

    If you know what unit you are interested in ask for the COP numbers and you can figure more precisely what your cost will be at each temperature. For a Goodman 3 ton 16 SEER I'm seeing $6.48 @ 60 degrees up to $10.50 @ 20 degrees. These may be more optimistic numbers, but still very good. And if the gas people are telling you the truth of $.80 in the winter, you can rerun the numbers to determine your balance point, and set your tstat to lock out the HP (make sure you get a tstat that can lock out HP).

    I would also go with a dual fuel, but be wary of 2 stage. From all the posts it appears they can be tricky animals for the reasons mentioned.

  7. #7
    Join Date
    Jun 2008
    Posts
    58
    We are planning on going with the lennox xp16 heat pump with the g61v as the backup or if going ac/gas it was the xc16 and the g71

    the xp 16 is upto 17 seer and hspf of 8.7

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