# duct a range hood into garage?



## jeff1 (Dec 17, 2003)

Hi,

A copy from Broan....

Can I exhaust my hood into my attic instead of out the roof or wall?

No. You should never exhaust air into spaces within walls, ceilings, attics, crawl spaces or garages. The humidity and grease collect in the space. 

http://www.broan.com/display/router.asp?docid=123

jeff.


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## Michael Thomas (Jan 27, 2008)

For future reference:



RANGE HOODS M1502.1 General. *Range hoods shall discharge to the outdoors through a single-wall duct.* The duct serving the hood shall have a smooth interior surface, shall be air tight and shall be equipped with a backdraft damper. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.

Exception: Where installed in accordance with the manufacturer's installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.

IMO the exception was pretty clearly intended to allow the "recirc" hoods that vent back into their immediate environment, I doubt any manufacturer's installation instructions will allow venting to a garage, see below.


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## troubleseeker (Sep 25, 2006)

Duct it through the wall, then turn up and go into the attic to get outside. A little wood or sheetrock chase will finish it asthetically, and it will be vented properly. Use rectangular duct up the wall, and it will not stick out so far as round. Once in the attic, you can go back to round, as it is easier to work using adjustable elbows.


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## Tattoo (Jan 6, 2008)

My MAJOR concern with ducting this way is with exhaust fumes entering the house from the garage. NEVER do this.....:no: :no: :no:


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## troubleseeker (Sep 25, 2006)

Tattoo said:


> My MAJOR concern with ducting this way is with exhaust fumes entering the house from the garage. NEVER do this.....:no: :no: :no:


If the duct joints are sealed with foil tape as they should be, the wall penetration caulked as it should be, and you build a taped and floated sheetrock chase , or even a caulked and painted plywood chase , is is everybit as resistent to any type of exhaust fume penetration as the dividing wall, and most likely more secure than the adjoining door into the house.:yes: . Besides that, you should not be running your car in a closed garage anyway.


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## Tattoo (Jan 6, 2008)

Troubleseeker you are absolutely right if he were to be running the ducting through the garage and continuing to an outside vent. Perhaps I misunderstood the op.... I thought he was considering venting directly into the garage.... which would be completely wrong :no: :no: ..... as per my origonal post....

Cheers


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## joasis (May 28, 2006)

There is a duct shaped specifically for going up the wall cavity, and then you can transition to a round pipe to penetrate the roof. Most hoods have knockouts for the rectangular shaped duct, which is made just for this application.


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## troubleseeker (Sep 25, 2006)

joasis said:


> There is a duct shaped specifically for going up the wall cavity, and then you can transition to a round pipe to penetrate the roof. Most hoods have knockouts for the rectangular shaped duct, which is made just for this application.


While the 3 1/2 x 12" rectangular duct you refer to will indeed fit in a stud cavity, it would entail busting the wall open to install it, and worse, in order to get into the attic with it, he would have to cut away the top plates of the wall. A lot simplier IMO to just go up the garage wall and enclosew the duct for asthetics.


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