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  1. #1

    Return Air Grills - Self Closing

    Does anyone manufacture a self-closing, louvered cold air return grill? The purpose would be to open when the furnace cuts on and then close by gravity when the unit shuts off. I've noticed air flowing back into the furnace when I have changed the filters. This unit is in the attic. Thanks.

  2. #2
    Join Date
    Jan 2010
    Location
    Nacogdoches
    Posts
    15
    sorry, but I have not.

  3. #3
    Join Date
    Feb 2004
    Location
    chicago suburbs
    Posts
    4,422
    Quote Originally Posted by skippytheloon View Post
    sorry, but I have not.
    thanks for sharing.

  4. #4
    Join Date
    Feb 2004
    Location
    chicago suburbs
    Posts
    4,422
    what you want is a back draft damper..but i don't know why.

  5. #5
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    Quote Originally Posted by William T View Post
    Does anyone manufacture a self-closing, louvered cold air return grill? The purpose would be to open when the furnace cuts on and then close by gravity when the unit shuts off. I've noticed air flowing back into the furnace when I have changed the filters. This unit is in the attic. Thanks.
    Is your filter in or next to the furnace in the attic? Or is it in the ceiling in a hall right below the attic?

    If you're feeling cold air waft down into the house through the ceiling return (if that is where it is, since I don't see it in your post), your ducts in the attic have leaks, which should be sealed, period. Duct leaks cost you money year round, so money you spend to fix them will be money you save to run your heating and cooling for comfort.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  6. #6

    filter position

    The filter is located inside the furnace between the cold air return and the fan. The cold air return ducts - 2 large ones - bring air to the furnace from the upstairs rooms. The cold air return grills are located in the ceiling of the upstairs - in a couple of different areas.

    When I pulled out the filter and replaced with a new one, I noticed some gentle air movement coming from the cold air return into the furnace. The furnace is located in the attic and with the return air grills located in the ceiling, it seems to make sense that warm air would have a tendency to rise from the conditioned space below and move back thru the ducts.

    This is a small gas furnace that heats a second floor in my home.

    Thanks.
    Last edited by William T; 01-25-2010 at 09:53 PM. Reason: clarification

  7. #7
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    When you have the access door off to change your filter in the furnace, and the attic is cold in comparison to the house, you will see air move up from the house and out through the door you removed to change the filter.

    The question might rather be if this is occurring when you have the door on and the furnace is not running. It could be if you have substantial leakage in the return and supply side ducting in the attic.

    If this possibility concerns you, you can have your ducts tested for leakage by an energy auditor with a "duct blaster" kit. This test is most useful if not only the amount of duct leakage is determined, but the location of the leakage areas are found. The latter part is not always easy, for it depends on how accessible the ducts are in the attic. Major leakage points in ducting tend to be at the supply and return plenums, with fittings further away being a close second.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  8. #8
    Join Date
    Aug 2009
    Posts
    164
    It sounds like you don't have all that much duct in the attic. The cheap and easy fix would be too buy a couple of roles of duct tape and cover all joints and the seam where the ducts were pounded together. That should take care of any leak issues unless you find a very large opening.

  9. #9
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304
    Quote Originally Posted by Big Unit View Post
    It sounds like you don't have all that much duct in the attic. The cheap and easy fix would be too buy a couple of roles of duct tape and cover all joints and the seam where the ducts were pounded together. That should take care of any leak issues unless you find a very large opening.
    A professional member recommends duct tape?

  10. #10
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    Quote Originally Posted by Big Unit View Post
    It sounds like you don't have all that much duct in the attic. The cheap and easy fix would be too buy a couple of roles of duct tape and cover all joints and the seam where the ducts were pounded together. That should take care of any leak issues unless you find a very large opening.
    The absolute most worthless use for duct tape is to use it on ducts in an attic. Oh, the irony!

    Duct mastic in attics is the way to go. If the leak gap is considerable, scrim tape and mastic will do it. If it is really large, the connection should be redone. Large leaks are generally signs of poor workmanship (excluding damage caused by other means).

    Save the duct tape for the "Red Green Show".
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  11. #11
    Join Date
    Aug 2009
    Posts
    164
    I do agree that mastic is much better. Most all new construction resi. projects that i've worked on, which is not many because I generally do commercial, are now spec'd out too have the ducts sealed with a foil tape or mastic. So although mastic is better, tape will cut down the draft and is much cheaper and easier and for the most part will get the job done.

  12. #12
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    Quote Originally Posted by Big Unit View Post
    I do agree that mastic is much better. Most all new construction resi. projects that i've worked on, which is not many because I generally do commercial, are now spec'd out too have the ducts sealed with a foil tape or mastic. So although mastic is better, tape will cut down the draft and is much cheaper and easier and for the most part will get the job done.
    Taping vs. buttering mastic on good joints to make them more airtight being cheaper and easier? Hmm...

    Foil tape can be okay...I just like the peace of mind of a sealant that is much more resistant to breaking down in the cruel conditions we subject ducts to than tape generally is. Gray duct tape...fuggetaboutit.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

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