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JoulesWinfield 12-27-2006 07:35 AM

Adding a basement bedroom
As the title states Im adding a bedroom in my basement.
I am trying to figure out how to properly move the existing overhead heat duct and add a cold air return to the bedroom.

I could eaisly shorten the run for the heat duct and drop it into the nearest interior wall for the heat duct to be near the floor, but Im not sure if that is the way to go.

The other half of the problem is that there isnt a clear floor joist that enters the area for the new room from the cold air line.

What can I do for this? All of the heat runs are a tubular type system as well as many of the cold air runs. Is there a system that I could split one of the joists to run two lines, one heat and one return?

Thanks guys.

Hube 12-27-2006 11:54 AM

A supply and a return in this bedroom is the way to go.
Now,in order to give some proper advice we need some info; what size is this Bedroom? LXWXH. What is the size of the EXTERIOR walls that will border this Bedroom? is there insulation in these exterior walls? what is the R value?

Since hot air rises, it is better to have both the supply low at floor level. The return should also be on an opposite wall, and as far away from the supply as possible.
Post back with the sizes,etc, and we can give some more exact info.

glennjanie 12-27-2006 10:17 PM

Hube has some valid points there. I would like to add some thoughts from my view; if you can use them, great! if you can't, just trash them.
You mentioned an existing overhead duct, do you also have an open return air grille anywhere in the basement? I agree hot air rises but cold air also falls; that being the case I would use the existing overhead duct for the supply. You also mentioned earlier that you had a vent already cut near the floor; if you do have a return air opening in the basement you could just put a grille on the existing vent and let the air find its way back to the return duct.
One other point, supply air should not be run through the joist space in contact with the wood. If it is in a duct its OK but not just by paning the joists.

JoulesWinfield 12-28-2006 05:23 AM

Thanks guys.
The size of the room is about 8'-8" x 13'-4". I say about cause Im not totally done drawing it.

If you check my post in the Framing section (Post#9), I have a drawing that is pretty close to current. Im planning on adding R13 in the finished portion of the exterior walls but probably nothing in the closeted area for the washer + dryer.

As far as a return in the basement, I think there is one but its just a grille installed right into the duct work. Later I plan to closet in the furnace and water heater with a louvered door, would that still work to draw return air from the bedroom? The rest of the basement will be finished, but open space.

Hube 12-28-2006 07:37 AM

Panning or joist lining in most areas (code) is ok for return, but NEVER for warm air supply runs
And yes, cold air does fall, and that's all the more reason for installing BOTH supply and return low (especially in a basement area.)

glennjanie 12-28-2006 09:34 AM

This is not intended to be offensive to anyone but my opinion is; the return is sufficient for the purpose and the ceiling duct will work. A round heat diffuser on the ceiling will spread the warm or cold air around the room just fine. Basement space is very easy to heat and cool because it is temperature stabilized by the ground around it. Re-doing the supply and return air ducts probably would be more efficient but I was considering the cost and degree of difficulty. Please post back and let us know how it turns out.

JoulesWinfield 01-02-2007 05:09 AM

Thanks Glenn and Hube.
I think I have it figured out. My brother told me that it is ok to split an existing cold air return and run it to this room as well. Is that correct?
If it is than I can run that to the SE corner and it would be pretty easy to run the heat in the NW corner of the room.

Hube 01-02-2007 08:21 AM

as your Brother suggested it is ok to split a Return.
However, is the portion of this return your going to split and take from this room adequate to satisfy the amount of incoming supply.?
it's all a matter of Math.
for instance; if you install a supply of say 6" diam (approx 28" area)..then you should have AT LEAST 28 sq inches of return ,slightly more is better.

in that case a 3 x 10 return duct terminating with a 6 x 10 grille would do the trick.
Ps; keep in mind though, when you "split" a return you also "rob" from another area.

glennjanie 01-02-2007 08:22 AM

Sounds perfect to me Joules. While the supply air travels under pressure to its destination, the return simply allows the air to find a route of flow. Across the corners like that should mix the room air very well.

JoulesWinfield 01-02-2007 12:20 PM

Great thanks guys.
The return Im thinking of splitting is one that uses the whole space between floor joists and it only goes to one room so I think that will be sufficient for the two rooms.

For the heat supply I will cut back the vent that is in the ceiling and run it into the wall down low.

I really wanted to get this right cause my old house had the vents in the ceiling in the basement and it always felt cold down there.

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