doesn't compute
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Thread: doesn't compute

  1. #1
    Join Date
    Apr 2005
    Location
    Welland, Ontario, Canada
    Posts
    68
    2 dealers have made the same recommendation for my home.
    either a Trane XV90 with stage 1 of 37000, stage 2 56000,variable speed fan,
    or a Trane XR90 single stage 38000 btu.
    How can they suggest a 2 stage variable speed furnace with a first stage that is as large as the single stage furnaces
    entire output.
    To me it means the extra expense for dual stage is money for nothing, other than the variable speed fan.
    What gives?
    The price difference is about $1000

  2. #2
    Join Date
    Dec 2002
    Location
    Toledo, Ohio, United States
    Posts
    12,899
    Unless I'm missing something it sounds like you answered your own question.
    No Heat No Cool You need Action Fast

  3. #3
    Join Date
    Apr 2005
    Location
    Farmingdale NJ
    Posts
    36
    How big is your house..Did they do a heat loss heat gain to determine proper sizing

  4. #4
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    twilli3967
    Professional Member

    is right you already answered your own question
    at 38,000 btu why would you need two stage. nothing to gainas far as i can see
    put in the 90 percent and save money all around

  5. #5
    Join Date
    Apr 2005
    Location
    Welland, Ontario, Canada
    Posts
    68
    My house is about 1000 sq ft. and a semi-detached with a common wall. It is a 2 storey with exposed walls on the east west and north sides

  6. #6
    Join Date
    Oct 2004
    Posts
    3,400
    The advantage of a variable speed is better humidity control.



  7. #7
    Join Date
    Dec 2002
    Location
    Toledo, Ohio, United States
    Posts
    12,899
    That's a lot of Mo to get rid of a little R/H.

    But they are right upgrade if your air cleaning 24/7 the money you save on electric will eventually even out. And it will increase the seer of your A/C

    My choice would be the single stage
    No Heat No Cool You need Action Fast

  8. #8
    Join Date
    Mar 2004
    Posts
    1,042
    The only advantage of the second stage will show up when you come home from vacation and want to heat the place up quickly. The benefit of the fancier unit will primarily be the variable speed blower, not the second (unnecessary) heating stage.

    But what gives?

    They'd recommend a smaller 2-stage unit if they existed, but that's about as small as they come in most brands. I had the same quandry when I had the system in my condo replaced. They used to make furnaces with a single heating stage and a variable speed blower, but those have largely disappeared. Now to get variable speed you pretty much have to get two heating stages, and in some applications those just aren't available in suitably small sizes.

    If you really want top of the line equipment and want to take real advantage of having the two heating stages that always seems to come with it these days, get a Carrier guy to write you a quote. They have an unusually small two stage variable speed furnace, the 58MVP040. Though it may be wider than the Tranes you're looking at, it's extraordinarily efficient (96.6% in upflow configuration). The output is 25,000 on the first stage and 37-38,000 for the second (input 26k/40k). It sounds like the ideal furnace for your application, if you really do want variable speed. I don't know of anybody else that makes a comparable furnace that's this small in output.

  9. #9
    Join Date
    Apr 2005
    Location
    Kingston Ontario Canada
    Posts
    1,210
    Sounds like a plan to me, Lad

  10. #10
    I would look for diffenent equipment that can offer a better size for your application. Something like a 50K, 2-stage, variable speed unit.

    Like this one or this one, which is a modulating unit.

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