Do I have enough air returns
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  1. #1

    Do I have enough air returns

    I have a two story house approx. 2300 square feet. I have a 5 ton single unit. One contractor told be a need another air return. Currently I have one air return that hold two 16x20x1 air filters. I buy the more expensive 3M filters because they are a little more sturdy. The cheaper one tend to fold in from the vacuum.

    How do I know how big the air return should be for a 5 ton unit?

  2. #2
    Join Date
    Oct 2006
    Location
    The Beach
    Posts
    674
    We use 200 sq. inches of return grill size per ton. With the proper size return ducts. And at least one return on each floor.
    Blue Fox

  3. #3
    So with a 5 ton unit I need 1000 square inches. What size should the return duct be for 1000 square inches?

  4. #4
    Join Date
    Jul 2008
    Location
    Rochester NY
    Posts
    4,695
    About 36% bigger than 640.

    You got yourself 3 gallons milk and only 2 jugs. System heat n cool ok? Then unit probably oversized. If not, ductwork probably undersized. Either way sounds like a mismatch.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    DO THE NUMBERS! Step on a HOMESCALE.
    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to BPI.org, or RESNET, and find an auditor near you.

  5. #5
    I live in the Houston area FYI... The system heats well, but sometimes in the summer it has a hard time keeping up. The unit is 5 tons for 2300 square feet.

  6. #6
    Join Date
    Nov 2004
    Location
    Agawam, Ma
    Posts
    43
    2-25x20x1 filters, and maybe try another pleated filter. The 3M can too restrictive.

  7. #7
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    20,777
    Quote Originally Posted by stone-cold99 View Post
    2-25x20x1 filters, and maybe try another pleated filter. The 3M can too restrictive.
    This would be a good start, but the extra return duct is a MUST! If the system cannot suck enough air, it cannot deliver enough air.

    I grew up in Houston, I know how brutal the summers can be. Get the system pumping enough air and you will feel better. While you are at it, have a qualified tech come out and clean/service your unit. Might find some details that will help it run more efficiently.
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  8. #8
    Join Date
    Apr 2006
    Location
    Houston, Texas
    Posts
    40
    Quote Originally Posted by stone-cold99 View Post
    2-25x20x1 filters, and maybe try another pleated filter. The 3M can too restrictive.
    & minimum duct on each should not be less than 16"

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