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Hot air duct system re-work

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Jon_blaney
Jon_blaney Member Posts: 318
I am going to downsize two 8" round ducts which run to a room which generally overheats installing new 7" ducts. I will run new a new 6" ducts to a room which now has none. Can I just use reducers at each end or do I need to run all new ducts? I want to avoid new boots at the floor terminations. Are round ducts better than rectangular?

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  • Ironman
    Ironman Member Posts: 7,379
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    You can do it any way that you like, but that doesn't mean that you'll get the results you want.

    Ducting, like hydronics, requires proper design and sizing based upon the heat gain/loss for each room. Without knowing that and your present duct layout, there's no way to confirm it will be adequate.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • HVACNUT
    HVACNUT Member Posts: 5,865
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    Installing a return in the overheated room, up high if possible, might help.
    Where is the thermostat in relation to that room?
  • DZoro
    DZoro Member Posts: 1,048
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    Maybe install a simple duct damper? Do you have air conditioning? If so is that also the coldest room?
  • Ken D.
    Ken D. Member Posts: 836
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    if the system does Heat and AC, the duct system must be adequate to carry the cooling load. AC requires more cubic feet per minute airflow than heat. Balancing dampers do work.
  • Ken D.
    Ken D. Member Posts: 836
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    Round ducts are better in the respect that the elbows are radiused, allowing for smoother airflow- unless the rectangular duct has radiused elbows. Found is also easier to install.