DIY Home Improvement, Remodeling & Repair Forum

DIY Home Improvement, Remodeling & Repair Forum (http://www.houserepairtalk.com/forum.php)
-   Plumbing Forum (http://www.houserepairtalk.com/f33/)
-   -   Is there a solution for horizontal hood duct? (http://www.houserepairtalk.com/f33/there-solution-horizontal-hood-duct-8722/)

ilyaz 02-23-2010 05:40 PM

Is there a solution for horizontal hood duct?
 
1 Attachment(s)
We are putting in a range hood in the kitchen. The X in the photo shows its approximate location. We want to have a horizontal duct as shown. However, the vertical studs are all 3.5" wide. We can't make the wall thicker since in this case we won't have enough space for the cabinets. Is there any way of feeding some sort of hood duct horizontally as shown without extending the wall?

If not, we will consider either a vertical duct or no duct at all, but that would be Plan B.

Thanks!

Wuzzat? 02-23-2010 06:27 PM

What dia. vent pipe is recommended for that distance?
How deep are the cabinets?
What's on the other side of the wall?

ilyaz 02-23-2010 07:46 PM

Quote:

Originally Posted by Wuzzat? (Post 41335)
What dia. vent pipe is recommended for that distance?
How deep are the cabinets?
What's on the other side of the wall?

The hood we're getting is this: http://broan.com/ImageLibrary/broan/pdf/InstallGuides/626978C.pdf
It states that for horizontal it's "3¼” x 10” only"

The bottom cabinets along the hood wall is about 25 3/4".

On the other side are two bathrooms.

Wuzzat? 02-23-2010 08:01 PM

Quote:

Originally Posted by ilyaz (Post 41338)
The hood we're getting is this: http://broan.com/ImageLibrary/broan/pdf/InstallGuides/626978C.pdf
It states that for horizontal it's "3¼” x 10” only"

The bottom cabinets along the hood wall is about 25 3/4".

On the other side are two bathrooms.

If you can stand losing 3-1/4" out of your 25-3/4" deep cabinets you can run the duct through them.
This rectangular duct is 32.5" in² in area. If you can fabricate a duct 1" or 2" deep by whatever height it takes to make the same cross sectional area, that might work and it would hardly infringe on your cabinet depth. But, people usually don't make ducts shaped like this, and probably for good reason.

Maybe you could run several small round ducts to make up the duct area.

This hood has uses up to 300 CFM, which would be an air velocity of 300/[32.5/144] = 1400 FPM in that duct. I'd think air moving that fast would be noisy.
You might want to use
Engineering ToolBox
or other sites to check how well different duct shapes will work.
Maybe at the distant end you'd need a booster fan.

Work all this out before you lift a hammer.

ilyaz 02-23-2010 08:14 PM

Quote:

Originally Posted by Wuzzat? (Post 41339)
If you can stand losing 3-1/4" out of your 25-3/4" deep cabinets you can run the duct through them.
This rectangular duct is 32.5" in² in area. If you can fabricate a duct 1" or 2" deep by whatever height it takes to make the same cross sectional area, that might work and it would hardly infringe on your cabinet depth.

Hmm, I need to think about this one. Actually, I would be cutting through the wall cabinets not the bottom cabinets, and the wall ones are certainly not as deep (not sure about their exact depth).

Are you saying that two ducts with the same area, lengths and number of turns are identical in terms of how well the air pushed through them, how loud they are etc?

Thanks.

Wuzzat? 02-23-2010 08:23 PM

Quote:

Originally Posted by ilyaz (Post 41340)
Are you saying that two ducts with the same area, lengths and number of turns are identical in terms of how well the air pushed through them, how loud they are etc?

Thanks.

Most of our wall cabinets are 12" deep.

The total area of separate ducts may have to be more than 32.5 sq. in.
The engineering site may tell you how many of what size round ducts is equivalent in resistance to the rect. duct.
You'd have to have a sheet metal shop make up a manifold to go from the hood opening to these round ducts, or you could do it yourself. I'd make a cardboard mockup first. If you don't round the corners air turbulence messes up the calculations and makes noise.

inspectorD 02-23-2010 08:56 PM

well
 
Are there soffits going in above the upper cabinets? and which way do the floor joists run.

ilyaz 02-23-2010 09:22 PM

Quote:

Originally Posted by inspectorD (Post 41348)
Are there soffits going in above the upper cabinets? and which way do the floor joists run.

No soffits.

Joists parallel to the red line in the photo (I think)

inspectorD 02-24-2010 05:47 AM

well
 
If you can, run the ductwork in the joist cavity, just sheetrock the inside of that bay for fire codes...check with your local building official first.

Other than that, they also make downdraft hoods..which is better than nothing.But $$

Wuzzat? 02-24-2010 03:00 PM

Or go through the wall and make a small
http://www.enonhall.com/images/04132006/duct.jpg
in the bathroom.

With large CFM blowers, if you have gas appliances, careful you don't remove too much of the Combustion Air from your house.


All times are GMT -6. The time now is 07:38 AM.