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Thread: what size

  1. #1
    Join Date
    Jul 2006
    Location
    Elma, WA (far west)
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    Confused

    I have a 1427 SQFT, single story home in western washington.
    5 large windows, (3 x 4 foot) two small windows, 2 x 2, 2 doors, 8 foot ceiling. I recently had a HVAC salesman look at my house and he just said, a two ton unit would work perfectly in your house. Does this sound about right? he didn't do any kind of in-house walk around or anything else, just noticed that I had a Trane two stage XL90 gas furnace and he said the coils would fit right under that and a two ton unit outside would never be working too hard. is this normal procedure? does 2 ton sound about right?

  2. #2
    Join Date
    Dec 2005
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    783
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    Have him do the calculations and get back to you. Also I would suggest that you get a least one more bid on your job and they should also do the calculations and not guess at the size.

  3. #3
    Join Date
    Mar 2006
    Location
    The South
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    Craiga,

    What is the model number of your XL90 gas furnace? What is your electric rate? You might consider pairing a heat pump with gas furnace for possible savings in heating mode(dual fuel). No longer is nat gas a value fuel for winter heating and a heat pump might be a good addition for your relatively mild winters and save you some dollars. I would think a 2 1/2 ton would be a better choice but you won't know for certain without a professionally performed load calculation. Also your ductwork should be checked for size, overall condition, supplies/returns, insulation properties, and any airflow issues.

    My opinion.

  4. #4
    Join Date
    Apr 2006
    Location
    Parma, OH
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    387
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    Just responded to a similar post. As stated here, calculations are important. You need a Manual J calculation done. Do a google search for "Manual J calculation" and you'll see why. Don't trust them to look around and hit on a number. What might that say about the rest of the work they do. . .?
    Terry McIver, Content Director, ContractingBusiness.com magazine.

  5. #5
    Join Date
    Jul 2006
    Location
    Elma, WA (far west)
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    re: what size

    Wow, I had no idea what all went in to figuring out what size ac unit to put in to the house. I think for now, I will have another contractor come in and check the ductwork, and do a full load analysis on the house before I make any decisions. I do know that our electricity rate is higher than NG, but by how much I"m not sure. Lots of homework to do. thanks for all your help.

  6. #6
    Join Date
    Feb 2006
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    478
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    Don't forget to check the ductwork using Manual D, after getting the right sized AC. You might have to modify the ductwork.

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