A Few Questions About Air Returns - HVAC - DIY Chatroom Home Improvement Forum

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Old 02-17-2012, 08:54 AM   #1
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A few questions about air returns

Hi there, I've done some searching but it seems that almost everyone has a little bit different situation so far...

I realize that it's hard to give me answers without being at my house to see but if you could just give me your opinions based on what I'm writing here, I'd appreciate it!

Some background: Furnace is a bit oversized based on a load calculation I had done while quoting an air conditioner, the thermostat is also in a smaller room with a supply that is very forceful, these two things together cause the furnace to be on for short times during the day only...I don't know if this matters. The house is a side split with an unfinished basement (1600 sqft finished). There are no doors separating levels except for the unconditioned basement space.

Here are my current returns:
Top level:
1. Master bedroom in the floor about 7"x12" (little flow)
2. Second bedroom in the floor about 7"x12" (little flow)
3. Hall outside master and 3rd bedroom about 24"x7" (med flow)
Main Level:
4. Dining room under thermostat about 24"x7" (very high flow)
Lower level:
5. Hall about 15"x10" (med flow)
6. Rec room about 10"x5" (very little flow)


Return 3: can I eliminate this one if I put in another small return in the 3rd (small) bedroom so all the returns in the bedroom will flow more? The return is connected to the trunk by 5-6" holes drilled the the floor joists

Return 4: this one is right close to the furnace and if I don't put tape on the back of it, the metal fins will howl in the "wind" LOL. Any way I can slow this one down to force more air suction from other returns?

Return 5: this one is using the stud spaces of a wall I want to do some soundproofing on...can a return be moved up to close to the ceiling so that I can put safe 'n sound in the stud space below?

Return 6: This one is connected to the two bedroom returns and I was considering blocking it off altogether, plus it's only about 8 feet away from a gas fireplace. I'm uncertain whether this will make the room even stuffier though. This room is off the hall with the only other lower level return in it.

I know this is a long post but any opinions on any of these would be appreciated!



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Old 02-17-2012, 03:30 PM   #2
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Don't know how to answer you,as I don't care for any of your suggestions.
In 30 plus years I have never seen a house with too many returns while I have seen way more than you would imagine that have had too few.
If you understand how air moves in your house you would see what your problems might be.
Say in one room you have a supply but no return .If the supply is trying to put warm air into that room it has to push against the air already in that room.Its literly like trying to blow into an empty soda bottle,you can't do it.Thus you end up with an uncomfortable room.
A furnace or a/c must be able to breathe easily in order to work as it was designed and to last as long as it should without repairs.
The other thing I see a lot of is single return which might be sized correctly for the equipment but the rooms are a mix of tempatures and comfort.
Return air is a system in the house and needed for the equipment.Both situations must be considered.
You are probably ok on the returns with little air flow felt,but on those grilles where you feel a lot of movement,you could probably increase the comfort by increasing the size or by adding another return to that room.
Hope that helps you.


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Old 02-17-2012, 07:43 PM   #3
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REP, thanks for your reply. I understand all of the stuff you were saying there...I'm just making sure that there isn't some reason I'm overlooking when thinking of how to better balance some of the returns.

I'm not sure I'm on the same page as you with the comment about increasing the size of the return in the room that has too much flow though. This room is first on the supply line and closest to the blower on the return trunk. Since the blower will try to pull air through the path of least resistance it currently gets a large portion of it's return air from this one vent, increasing it's size would only compound my problem I'd think.

My goal is to balance out the return air as best as I can throughout the house.

I will, however, take your suggestion on never seeing a house with too many returns and leave the small return in the basement alone.
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Old 02-18-2012, 04:00 AM   #4
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Balance your supplies, if you have rooms that over or under heat.

May need to add more return.
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Old 02-18-2012, 12:31 PM   #5
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Thanks, I'll see what I can do about getting some sort of flow meter, and add the return in the bedroom or anywhere else I can that makes sense.

Any opinions on moving the one return to the top if the hallway wall?
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