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condenser sizing

Gererically speaking is there a rule of thumb on condenser sizing for sq footage of conditioned space, 2880 sq ft.


  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541
    Heat gain

    A Manual J is needed to size the system.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • don_9
    don_9 Member Posts: 395
    I agree

    I agree with Robert however if you are just doing a quick estimate and you believe to be with a tire kicker with the houses being built today sq x 17 will get you close enough.

    However let me say as Robert mention you need the correct number so you know what your shr number is.Without them you may not pick the correct unit to do the job.

    May I suggest a book from acca its the manual S residential equipment selection.This will show you how to properly size equipment.
  • Tim_75
    Tim_75 Member Posts: 44

    There are rules of thumb, but they're wrong. An experienced individual can make a very acurate guess based on location, contruction, square footage, occupancy and exposure. Usually, those guesses are backed-up by load calculations before mistakes get made. Or, mistakes get made.
  • Empire_2
    Empire_2 Member Posts: 2,343
    Man. "J"

    I agree a full load calculation should be done.  But try this.  It will get you close like Don said.  Cubic foot x 5 air changes per hour (divided by 60 min.) divided by 400 cfm/ton.

    Mike T.
  • John Mills_5
    John Mills_5 Member Posts: 951
    the best way

    to size without a Manual J:

    stand across the street, hold your hand in front of your face. Fingers up. The # of fingers it takes to cover the house is the tons you need.

    Hey, it's as accurate as any other non load calc method!
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