move return air to floor?

Discussion in 'HVAC' started by Amber, Apr 4, 2008.

  1. Apr 4, 2008 #1

    Amber

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    I am tearing down walls to remodel my kitchen but one wall has a return air duct near the ceiling (no actual ducting in the wall, it's hollow between the studs.) There is only one other return air duct in the area (about ten feet away) but the room will be very open once the walls come down. There will be no interior walls left so my only foreseeable option is the floor. Can I have return air duct on the floor? Also there are cathedral ceilings in the area; no attic.
     
  2. Apr 4, 2008 #2

    handyguys

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    Amber - Warm air rises. That is why its high on the wall to maximize cooling efficiency. If you move it to the floor it may not do such a good job at keeping things cool in the summer. Moving it to the floor is better that eliminating it altogether. It wont hurt anything it may just make your system not work as well as it currently does.
     
  3. Apr 4, 2008 #3

    glennjanie

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    Welcome Amber:
    Your house sounds like it will be wide open when you finish with the walls. One return air filter-grille should do the job very well. The additional returns in seperate rooms are to keep those rooms in the loop of air; no walls? no need for additional returns. I hope this helps.
    Glenn
     
  4. Oct 15, 2015 #4

    68bucks

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    Well I'd like to revive this old thread rather than start another return air thread. I ran across it while searching and my question is similar to this thread but I'd like to drill down a little deeper on it. I am remolding a home and it is basically one room, open concept on the first floor. The room is almost 50'x25'. The kitchen occupies about 14'x14' in one corner. There is a small entry area on one end and a short (8') hall to the utility room. There is a return air grill on a wall near the entry and there was one on a partial wall separating the kitchen from the living area of the room. It faced that living area. Well that wall is gone and I need to move the return. However there are not many interior walls, basically none in the living area of the room.

    So what are my options. I can put it on an outside wall, not good I suspect. I can hide it in the kitchen cabinet toe kick area. I worry about drafts with that. I know usually no kitchen return because of odor but its all one room any way I figure. There is an upstairs bedroom that is open like a loft so its connected any way. There are 2 other bedrooms upstairs but they are off a separate furnace. Option 3 might be in the wall of the hallway to the utility room. With this there would be 2 returns near the entry only 8'-10' apart, close to the furnace but none at the other end of the room some 40' away. With this location I could put one up high on the wall, the other one is near the floor. Think the air flow from one end to the other would be OK and keep the room evenly heated? Only other thing I can some up with is in the floor somewhere but that would be tricky and not particularly attractive.
     
  5. Oct 19, 2015 #5

    frodo

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    can you provide a floor plan sketch?
     
  6. Oct 19, 2015 #6

    68bucks

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    This is pretty close I think. The hallway is new in the renovation. Prior there was a doorway into the utility and 1/2 bath through the wall in the kitchen and there were 2 closets in the entry area. We blew the back of the closet out to make the hallway and closed the kitchen wall opening. The clod air duct runs from furnace toward the return in the hall way as 2 joists panned then turns left in the sketch and heads as a duct toward the living area end of the room. The return in the old location was a panned joist over to the duct.

    HVAC.jpg
     
  7. Oct 19, 2015 #7

    Sparky617

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    As long as the hallway is open to the space at the doorway that should work as a location for the air return. Around here we have the filters behind the return grills so I'd avoid putting it in the floor as it would get a lot of dirt on the filter or in the duct w/o a filter there. I've never seen return ducts in the exterior walls so I'd avoid that. Supply comes in at the exterior walls, usually under windows and returns are in the interior of the house.

    A movable damper to allow you to have a high return and a low return works if you are doing both heating and cooling with the ducts. Use the high return in the summer to pull in hot air and the low return in the winter to pull in the cooler air.
     
  8. Oct 19, 2015 #8

    68bucks

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    If I put the return in the hallway I thought about putting that one up higher that would give me one high and one low, reasonable compromise. The hallway will be completely open no door or anything to block flow from the rest of the room.
     
  9. Oct 19, 2015 #9

    frodo

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    set the unit in the utility room, on a platform, with the return under the unit

    install a hole in the wall between utility room and kitchen with gril on both sides. above cabinets

    install grills high/low on the door to the utility room

    basically using the room as a plenum. instead of running duct

    120vac40a_rev.jpg
     
  10. Oct 19, 2015 #10

    68bucks

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    Not sure I can do any of that. I have floor to ceiling cabinets on the kitchen side of that wall, other than the back splash area. I have to double check but I think I'm almost tight to the ceiling on top of the furnace. Off the furnace cabinet there is a Space Guard filter then the plenum rolls over the top and goes vertically down through the floor into a crawl. The A coil is under the furnace at floor level now I believe. I can do vents in the door no problem but unless I can get it to the blower it won't help my return. If I had to put in a floor return I could do it in the utility room more or less accomplishing the same result as you suggested and at least the floor return would be in a better looking place. I don't really see how I would change the performance of the system much by returning the air from a new return in the new hallway vs. the louvers in the door and platform return or floor return in the utility room. It seems like my air flow through the room is still basically the same. I'm still pulling from one end of a large room. Thanks for the ideas.
     
  11. Oct 19, 2015 #11

    nealtw

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    Have you looked at the livingroom side of the island kick?
     
  12. Oct 19, 2015 #12

    68bucks

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    Yes I thought about that first. I think I'm most worried about if the cover will get all kicked in from people siting at the island. And to a lesser degree about the aesthetics. The back of the island will be all finished wood panel so a grill screwed to it might not look so god.
     
  13. Oct 19, 2015 #13

    nealtw

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  14. Oct 20, 2015 #14

    68bucks

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    That's an option, looks better. The back panels and cabinets are a Shaker design so the frame is a problem if I try and put them in the toe area of the cabinet. I'd be coming in from the back side of the cabinets.
     
  15. Oct 20, 2015 #15

    nealtw

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    This is a problem that nobody talks about when they talk about open concept.
    Perhaps with a little fancy wood work if the toe kick is recessed the up space behind the panel infront of the kick or at the top of the panel under the counter top.
     
  16. Oct 20, 2015 #16

    68bucks

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    That's what I was thinking about too. The cabinets are from a custom shop so I was going to challenge them to come up with something. I don't want to pay through the nose any more than I am though.

    So based on your suggestions I'd say you don't think the air flow/room condition would be good with all the return air at one end of the room. That's the bottom line I guess. I mean the furnace will operate fine as long as I give it ample supply air. There are 8 supply vents in the room that's about 1100 sf with 8' - 9' ceilings. There is also an open staircase to the second floor right by where the return ducts would be. I'm not sure how airflow down that stairs might play in. Seems if I blow air through vents in the far end of the room it has to flow toward the other end. I'm just trying to convince myself that the room will be comfortable. Thanks for the response and suggestions.
     
  17. Oct 20, 2015 #17

    bud16415

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    For what it’s worth. When I redid my kitchen two years ago the pantry cupboard sat above the return. I cut out the toe kick to look like two legs with a curve in the corners. The opening was large enough and I have no grate there. The return in the basement runs between the floor joists and I put an access panel into the duct in the basement for cleaning.
     
  18. Oct 20, 2015 #18

    nealtw

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    Not sure, I was suggesting ways to get them off the floor.
     
  19. Jan 6, 2016 #19

    68bucks

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    I thought it would be a good time to bring this tread up again and post what I did and the results, for what its worth. I added an updated sketch. What I ended up doing was installing two return points in the new hallway, near the floor. So now I essentially have all my air returning to an area in a about 10' diameter. There is a return upstairs too. The furnace seems to be operating just fine, no odd cycling or shutting off on limits. I had it gone through by a local HVAC company and everything checked out (except the igniter). Yesterday I installed a new Ecobee thermostat in the hallway not far from the new returns.

    That said, I have another question. Because of the unusual construction of the house the area of the hallway is considerably warmer than the main portion of the room. The 1/2 bath gets really warm and the furnace room does too. The upstairs bedroom is a loft type arrangement so there are no walls so warmer air tends to move up there. That is directly above the new hallway. When the blower kicks on the warmer air is pushed down from the loft and effects the thermostat, it rises really quickly so the furnace wanted to cycle off quickly. Once off the temp would drop back to the main room temp and restart. I ran the blower, no burner, and I can get 1.5° rise just from the airflow. I will be installing a ceiling fan soon to push the warm air down the stairwell from the loft area. So the Ecobee comes in. I run only from the remote sensor placed in the main living area of the room and so far the cycles seem more normal. Now the question. Would it be a good or bad idea to cut a return air opening into the return air duct in the furnace room to move the extra warm air around a bit? Its a down flow furnace so the duct is right there. I could install an adjustable louver to control it a little. It just seems like I'm wasting heat in that little utility room that would be better served in the living end of the house.
     
  20. Jan 6, 2016 #20

    oldognewtrick

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    Do you have any dampers on the supply runs to the vents? Do the vents have dampers you can close or adjust to balance the air flow?
     

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