Questions about adding AC by tapping into my Central Air unit

Discussion in 'Home Theater Projects' started by BrianKR, May 30, 2004.

  1. BrianKR

    BrianKR Second Unit

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    I am going to use 4 x 12 registers connected to 6" flexible ducts.

    Will 1 register for air and 1 for return be enough?

    Do I just connect the return into the AC ducting or would I benefit more by adding a booster fan to draw the air out?

    Can I use a remote to control the booster fan if I purchase one?

    What type of connector do I use to attach the flexible duct to the main unit (what's it called)?

    I have never messed with HVAC but is it wrong to assume it's fairly easy to do?
     
  2. Frank Zimkas

    Frank Zimkas Supporting Actor

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    Connecting to the existing supply trunk is fairly simple to do. You'll need to use a 6" Top Take-off if you are going to come off the topp of the trunk. If you are connecting the flex duct to the side then you'll need a 6" Start Collar.

    The quantity of supply ducts will depend on the size of your room.

    A single return located in the ceiling or near the ceiling should be adequate.

    Don't assume you need a booster fan, you might get adequate air flow without one.

    Adding a few ducts is fairly easy if done properly, but can cause lots of headaches if not done properly.

    Hope this helps.
     
  3. BrianKR

    BrianKR Second Unit

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    Thx for the input Frank.

    Do you have to cut into the side or top of the AC trunk?
    With the run of the return duct in the room I'm not sure if I can tap into the side (the top definitely isn't happening).

    I am going to make sure I take my time and do it properly. I want it to be air tight so when I am not using the room it wont take away from the 1st level of our home.
     
  4. Frank Zimkas

    Frank Zimkas Supporting Actor

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    You can do either. Cutting into the top makes it easier to place the new duct in the joist cavity without adding more bends and possibly kinking the flexduct. If you can't cut into the top then tapping into the side and using a start collar is fine. Use some silicon to seal the start collar/trunk joint. Connect the inner mylar portion of the flex duct with 3 or 4 zip screws (sheetmetal screws) and a few wraps of duct tape. Pull the insulation and outer linning over the area that you taped and secure with large zip-ties. Screw through the zip ties with 3-4 1" zip screws to secure the insulation to the start collar and the boot.

    FYI, The Boot is the sheet metal portion that the register/grill fits into.
     
  5. BrianKR

    BrianKR Second Unit

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    Thx for your help Frank!
    I installed the flexible ducts yesterday, 1 for air and 1 return, and it's awesome. The room is comfortable and the stale muggy feeling is gone.
     
  6. Frank Zimkas

    Frank Zimkas Supporting Actor

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    Sweet!! Any issues with noise from the ducts?
     
  7. BrianKR

    BrianKR Second Unit

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    When I close the register it has a slight whistle.
    A friend suggested I try purchasing a register made of wood with rubber flaps. He has them and says they are air tight.

    I am also thinking about adding a return in my AV closet for added ventilation.
     
  8. Frank Zimkas

    Frank Zimkas Supporting Actor

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    Whistling from the registers is not uncommon, just open them up a tiny bit at a time until the noise stops.

    Adding a return in the gear closet is a good idea, keeps the equipment cooler, therefore your room will stay cooler as well.
     

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