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Thread: Add extra return to improve cooling in finished attic?

  1. #1
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    Jan 2010
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    Add extra return to improve cooling in finished attic?

    Downstate NY, two story home with finished attic and basement, two zones of combined central air/hydronic heating. Downstairs unit serves 1st floor and basement. Upstairs unit serves 2nd floor and attic, which was originally purposed as storage but used as a playroom. Heating and cooling on the 2nd floor is perfectly adequate, but I'm trying to improve comfort in the attic. After hot sunny days, the attic will be about 8-10F higher than the 2nd floor as the heat radiates back down from the asphalt shingles. The ceiling is insualted and drywalled, but probably could have done with a reflective barrier or better insulation.

    The 2nd floor air handler is located in a corner attic crawlspace. The return is positioned centrally on the 2nd floor but with a long run to the air handler, almost 20' (horizontal about 8' between floor joists and another 12' of round insulated ~12" flex duct that runs horizontally behind the drywalled kneewall. The attic is fed by 2 8x8" supplies and has a small 12x12" return about 6' above floor level (it ducts separately to the air handler intake manifold).

    The question: if should be cheap to have a 2nd , large return register T'ed into the main flex duct in the attic, within 6' of the handler. Would that improve balance in the attic without impacting the 2nd floor too much? I'm not expecting parity in temperatures, just an improvement of a couple of degrees.

    I don't know the tonnage of the units offhand. I guess an alternative would be a window unit or a split.

  2. #2
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    Static pressure needs to be measured and a balancing act done.

  3. Likes kdean1 liked this post.
  4. #3
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    Quote Originally Posted by pecmsg View Post
    Static pressure needs to be measured and a balancing act done.
    X2, w/o knowing what you have, you are only guessing and gambling.

  5. #4
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    Thread Starter
    Yes I will look into having that done. I would guessimate that the 20' run from the 2nd floor return to the AH is not helping my system.

    As a general point, is adding a return grate on another floor (the attic in this case), in series with an existing return duct (from the 2nd floor to AH in attic), a dumb idea?

  6. #5
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    Quote Originally Posted by Dwalin View Post
    Yes I will look into having that done. I would guessimate that the 20' run from the 2nd floor return to the AH is not helping my system.

    As a general point, is adding a return grate on another floor (the attic in this case), in series with an existing return duct (from the 2nd floor to AH in attic), a dumb idea?
    Without a static pressure reading you can do anything you want.

  7. #6
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    Mar 2015
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    The returns might have to be in parallel w/ each other, & not in series.

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