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  1. #1

    cold/warm air return

    how does cold air return work for cooling in the summer? I have read that the cold air return should be at the ceiling level. to me this does not make sense and I am hoping that someone can explain the premise behind it.
    seems to me that drawing in the hot air close to the ceiling would make the AC spend more energy to cool off that air. If the cold air was returned to the system from the basement (where the cold air settles) it would take less energy to cool that air and push it thru the system (and viseversa in the winter).
    In my home, I have a large air return at the ceiling level on the ground floor, a small return on the floor in the addition and a medium return in the basement that goes directly into the air handler.

    I guess my questions are, can someone explain in laymans terms the idea behind cold/warm air return and
    should I block of the returns in the basement and the one in the addition or the one at the ceiling to help the cooling efficiency of my system.

    Thanks in advance!
    Charast

  2. #2
    Join Date
    Apr 2008
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    Alberta Canada
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    2,246

    It prevents stacking

    Quote Originally Posted by charast View Post
    how does cold air return work for cooling in the Thanks in advance!
    Charast

    You should not block any return air. But the whole reason is you want high wall returns is to remove heat from air and all your heat is trap higher in each room. it will still work but might take longer.
    Do it right the first time.

  3. #3
    Join Date
    Jan 2004
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    PA
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    68,784
    Do not block the returns.

    As far as more efficient pulling in the cold air in cooling season. Not really. The amount of moisture (not talking RH) in the air is still the same. But it harder to remove moisture from cool air, then it is from warm air.
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  4. #4
    Join Date
    Sep 2007
    Location
    Just North of Dallas, Texas
    Posts
    97
    Quote Originally Posted by charast View Post
    how does cold air return work for cooling in the summer? I have read that the cold air return should be at the ceiling level. to me this does not make sense and I am hoping that someone can explain the premise behind it.
    seems to me that drawing in the hot air close to the ceiling would make the AC spend more energy to cool off that air. If the cold air was returned to the system from the basement (where the cold air settles) it would take less energy to cool that air and push it thru the system (and viseversa in the winter).
    In my home, I have a large air return at the ceiling level on the ground floor, a small return on the floor in the addition and a medium return in the basement that goes directly into the air handler.

    I guess my questions are, can someone explain in laymans terms the idea behind cold/warm air return and
    should I block of the returns in the basement and the one in the addition or the one at the ceiling to help the cooling efficiency of my system.

    Thanks in advance!
    Charast
    I have to agree with the others, do not block off any of the registers. If the system was properly designed then they are a crucial part of the system to maintain temp balance throughout the room.

    However, I've puzzled for years why systems weren't designed with difference placements for heating and cooling. Down here in Texas there seems to be no cold air returns and the vents (output from the furnace/air handler) is located near the ceiling. While this may be optimal during the cooling season, I don't feel it's nearly as efficient during the heating season.

    My home in the North was opposite. The registers were located on the floor and each room had a cold air return. I gather since a lot of homes in the North didn't have AC (at the time) the systems were designed with heating in mind.

    Just another one of those quandaries ......

  5. #5
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,657
    Logically you would have 2 returns, 1 in the floor and 1 in the ceiling. Warm air rises and cold air falls. Unless you want to spend many $$$ making this happen, through the reconstruction of your home and installing a series of dampers and controls. Spend time pondering over something else and enjoy the heating and cooling of your house.

  6. #6
    Join Date
    Jul 2005
    Posts
    717
    Charast; The return location in the summer time is best taken from the HIGH (near ceiling) because that is where the heat is.
    The return in the winter time is best taken from the LOW (at floor) because that is where the cold is.
    To have both high/low return is very easily and very affordable by simply locating the return air passage in the SAME interior wall stud space. The LOW opening will have a register with a leaf type damper in it , and the HIGH will just have a damperless grille. In the heating season, the LOW register damper should be open, thus blocking off the high. In the cooling season ,the low damper should be closed, thus allowing air to enter into the HIGH opening.

  7. #7
    Join Date
    Sep 2007
    Location
    Just North of Dallas, Texas
    Posts
    97
    Quote Originally Posted by bmathews View Post
    Logically you would have 2 returns, 1 in the floor and 1 in the ceiling. Warm air rises and cold air falls. Unless you want to spend many $$$ making this happen, through the reconstruction of your home and installing a series of dampers and controls. Spend time pondering over something else and enjoy the heating and cooling of your house.
    I do enjoy the cooling of my home. However, heating while not nearly as predominant as cooling, is dispensed at the ceiling and not the cold concrete floors leaves something to be desired on those infrequent cold days.

    I do agree to change this at this juncture would be costly but I would consider the option of dual ducts in new construction.

    Thanks for the replies ....

  8. #8
    Join Date
    Dec 2007
    Location
    Cedar Grove, Wi-Sheboygan
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    Putting in a high wall and floor return air vents is not hard to do nor should it be that expensive to do as long as you have realtively easy access to wall cavitives that can be directed back to your main air return duct to your furnace/air handler. As it has been argued here and on other sites you can not have too much return air for your system as long as it is placed in the right areas of the home it will only benfit the homeowner and lower your H/C cost over the long run.

  9. #9
    Join Date
    Dec 2007
    Location
    Cedar Grove, Wi-Sheboygan
    Posts
    1,582
    Putting in a high wall and floor return air vents is not hard to do nor should it be that expensive to do as long as you have realtively easy access to wall cavitives that can be directed back to your main air return duct to your furnace/air handler. As it has been argued here and on other sites you can not have too much return air for your system as long as it is placed in the right areas of the home it will only benfit the homeowner and lower your H/C cost over the long run.

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