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  1. #1
    Join Date
    Jul 2005
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    I'll try to be direct -

    Loss/Gain Calculation = 21633
    Proposed Install = 21700

    Does this seem close?
    I was wondering if the L/G C should be matched with
    equipment "on the money" or if a "little more headroom"
    would be appropritate.

    Just interested in a different opinion about how the
    numbers add up with the equipment.

    Thanks in advance.

    Winter Outdoor Temp.: 1
    Summer Outdoor Temp.: 95

    Winter Indoor Design Temp: 70
    Summer Indoor Design Temp: 72

    Total Sensible Loss: 41659
    Total Sensible Gain: 16641

    Total Latent Loss: 0
    Total Latent Gain: 21633

    Total Btuh Gain: 2166
    Capacity Multiplier: 1.00
    A/C Unit BTUH Rating: 21633

    Install Proposal List:
    Trane XV80 80,000 BTU Model TUD080R9V3*
    Trane Cased Coil Model RXC025S3HP
    Trane XL 14i 2.0 Tons Model 4TTx4024*1000*

  2. #2
    Join Date
    Jun 2005
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    Your Cooling gain is a total of Latent(moisture)heat and Sensible heat gains. Do you have Total Cooling Load?

  3. #3
    Join Date
    Jul 2005
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    Thread Starter
    There's isn't a 'Total Cooling Load' number
    on the Trane contractors sheet.

    Besides walls/windows/ceilings/floors/etc... L/G numbers,
    there's a summary that reads:
    Nominal A/C Unit Size - 2.0
    Gas Furnace Output BTUH 41659
    Electric Furnace KW 12.2

    I'm wondering because other bids recommended
    2.5 ton and 100K BTU.

    The Trane 'Comfort Specialist' took window and sq.ft. measurments and the Software came up
    a half ton and 20K BTU's less then my other three bids.

    I'm going with the Trane System.

    The other bid's have made me nervous that I may be
    slightly undersizing.

    Just looking for some feedback before install next Wednesday.

  4. #4
    Join Date
    Aug 2002
    Office and warehouse in both Crystal River & New Port Richey ,FL
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    One of the load calculations is wrong,it needs to be correct to be of any value.

    Sensible 16thousand and latent 21000,sounds wrong,latent shouldn't be that high,check the numbers again.

    Id think he means ,21000 is the total with the latent and sensible together,thus a ton ton system ,is what he selected.Where are you located and size and type onstruction would help?

  5. #5
    Join Date
    Jul 2005
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    Thread Starter
    Located in Bloomington (central) Illinois.
    1980 Single story Ranch w/Basement.
    Main: 1,400 sq. feet - 8 ft. ceilings.
    Below Ground Basement: 530 sq. ft. - 7.5 ft. ceilings.
    Basement already has 2 supplies;
    Part of new install includes a return being added down there.

    -8 36" x 54" single pane windows with storm windows.
    4 facing south
    3 facing east
    1 facing north

    Framing is 2x4 and R-11.
    Original construction (Masonite) covered over with Vinyl siding.

    Asphalt shingle roof with soffit vents & ridge vent.

    Original Furnace: Rheem RGAA-100C
    Original A/C: Rheem, exterior labels missing.
    Original indoor coil: ? sealed in riveted sheet metal.

    Is any of this helping or making sense?



  6. #6
    Join Date
    Feb 2005
    Dothan, Al
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    Personally, I like the little extra - I would go with 2.5 ton, myself. As the home and unit get older, they may not be as tight or efficient. In my experience, in a few years, 2 ton may not do the job.
    And yet, it depends on whether comfort or efficiency is yur main concern. But if you want ther. set at 72 with 95 OAT, the extra surely wouldn't hurt.


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