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Old 02-28-2020, 11:57 PM   #1
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Info: I live in a 3 story townhouse with forced air. The hvac unit is located in the basement utility room.

Question: I am removing a non load bearing wall on the middle floor and currently plan to build a column around the return air duct which was in the wall and takes all of the top floor air down to the main return trunk.
Instead of building a column, can I just emove the ducting and put a grill on the ceiling, and another grill on the floor?

Is this something that can possibly work by pushing the return air from the top floor to the middle floor, then again from the middle to the main return via its original path?

Planning on either finishing the column tomorrow or putting on the grill covers depending on what all you smart folks tell me.

Thanks for your input!
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Old 02-29-2020, 03:55 AM   #2
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Re: Dumbest question award? (return air supply)


HVAC folks have been attempting to force warm air down for nearly as long as central forced air has been invented. To test your theory, with all the stair wells open ( no doors closed ) and all the 3rd floor room doors open, close off the return on the 3rd floor but disconnect the return from the main trunk in the basement so the unit will get plenty of air, and you can determine how it will work.
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Old 02-29-2020, 05:43 AM   #3
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Re: Dumbest question award? (return air supply)


I think it is a bad idea.

The furnace fan will suck air from the place of least resistance and w/o that duct attached to force it to take air from upstairs you will lose some circulation and comfort.

Basically it needs a duct to suck against and if that is gone it will take its air from the closer areas and you will end up with a lot less circulation upstairs.

It will take some but less and you will have cold spots.
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Old 02-29-2020, 06:14 AM   #4
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Re: Dumbest question award? (return air supply)


There are no dumb questions but this is close.

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Old 02-29-2020, 08:18 AM   #5
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Re: Dumbest question award? (return air supply)


+1 Yuri

If you try to pull return air from a 2nd floor ceiling grille across the 8' open space down to the grille in the 2nd floor, the amount of CFM coming from the 3rd floor would be . . . lets see . . . carry the 1 . . . divide by 144 . . . round up . . . equal to zero.

The ducted return on the 3rd floor is a large part of any semblance of cooling comfort you may have up there.

I'm guessing a column would severely hinder your plans. If you are going to that much trouble anyway, good planning might solve moving the duct somewhere.
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Old 02-29-2020, 08:32 AM   #6
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Re: Dumbest question award? (return air supply)


Maybe that's the cold draft they feel in haunted houses.
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Old 02-29-2020, 09:20 AM   #7
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Thank you all for the input!

Unfortunately the return ducting can't be moved anywhere else in the house, it's a small footprint. I had an hvac guy out here a few days ago to ask him that very question. However I hadn't had the brilliant idea to get rid of it yet, otherwise I would've asked him first.

Fortunately the column won't get in the way, so column it is!
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Old 02-29-2020, 09:36 AM   #8
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Re: Dumbest question award? (return air supply)


Quote:
Originally Posted by ThatGoogleGuy View Post
Thank you all for the input!

Unfortunately the return ducting can't be moved anywhere else in the house, it's a small footprint. I had an hvac guy out here a few days ago to ask him that very question. However I hadn't had the brilliant idea to get rid of it yet, otherwise I would've asked him first.

Fortunately the column won't get in the way, so column it is!
Not even with a fake beam and post system. Is it in the middle of the room.
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