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jlaky2000 11-26-2008 07:02 AM

Puzzling Ventilation Shaft in House
I have a question about my HVAC that I hope someone can help me with.

My furnace room is in the center of the house on the first floor of my two storey house. Next to the gas furnace flue there is a ventilation shaft, approximately 12" x 12" that runs from the furnace room into the attic. Does anyone know what purpose this shaft might serve? Could it be source of fresh air for the furnace to burn, or is it possible that I'm heating my attic (which I don't want to do...)? Should I stick a piece of insulation to plug the vent?

For background, my house was built in 1977 and we had the original furnace until last year, and I don't think that the old furnace used this vent.

1610 CUB 11-26-2008 09:16 AM

Could it be a laundry shoot? Hmmm

Daltex 11-26-2008 09:23 AM

It is most likely a fresh air intake for combustion air. Don't plug it up. Ask the installer of the new system to take a look and see if your new furnace is piped with pvc to get the combustion air or if it needs this chase to draw it from the attic. Post a pic of the furnace and it might help. You mentioning the "furnace flue" leads me to believe you need this fresh air supply.

hvaclover 11-26-2008 10:58 AM

Yep. Combustion air. You mentioned "furnace room". I gotta assume that is dedicated room just for the furnace? Is there a door on the room?

If so then the duct is a definite must to keep.

jlaky2000 11-26-2008 02:55 PM

From what you describe, it is probably a shaft to allow for air for combustion in the furnace. It certainly makes sense. There is a door to the furnace room and no PVC pipes to the outside.

hvaclover 11-26-2008 04:14 PM


Originally Posted by 1610 CUB (Post 190393)
Could it be a laundry shoot? Hmmm


Laundry shoot...God one 1610Cub! i sprayed my coffee all over the place!

BTW Happy Thanksgiving if i don't get chance to say it later.

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