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Furnace Closet Ventilation


My forced air NG furnace is installed in a closet. There are (2) 4 inch stove pipes that are also in the space that pass through the ceiling and ventilate into the attic. One opening is flush with the ceiling and the other opening is 24" from the floor. Needless to say I'm loosing a whole lot of heat. Is that much flow actually required? Is there anything I can do to mitigate the amount of air flow? Thanks

Re: Furnace Closet Ventilation

Yes, that much flow is required & has to be maintained.

The stove piping's main job is to PROVIDE SUFFICIENT AIR to the gas burners in order to burn the NG.

It takes 24 cu.ft. of air to burn one cu.ft. of NG---any restriction in this air amount will result in poor combustion & a dangerous situation.

Consult your local heating contractor (oil burner techs are also licensed to do gas heating)---they have sidewall vent systems (if the closet is next to an exterior wall), or in-line auto draft inducers that will vent thru the roof or (if you have one) a chimney, the open vents could be then closed off.

This could get expensive, so ask for several quotes.

Can't you just keep the closet door insulated & closed during the heating season??

Re: Furnace Closet Ventilation

Since the furnace closet has supplemental ventilation to the outside, you should make the closet otherwise airtight. This means weatherstripping the door and sealing any penetrations in the wall, floor, and ceiling, and sealing and insulating the ductwork in the closet. You might even place insulation board on the walls of the closet. This should mitigate most of the heat loss you are experiencing; any heat loss you do see afterward would probably be due to radiant losses from the furnace itself and the surrounding walls.

Blue RidgeParkway
Re: Furnace Closet Ventilation

You say both these "vents" terminate IN THE ATTIC? Are they open to the attic space, or do they go through the attic penetrate the roof or side wall and reach the OUTDOORS, or connect to a device - like a heat recovery ventillator - that then is connected to the OUTDOORS?

One opens near the ceiling of the closet and the other one near the floor?

No mention of a chimney or exaust flue.

Consult with a licensed HVAC technician on-site, your gas fired heating appliances should be cleaned, inspected and checked for tunning annually (preferably at the beginning of the heating season) and bring these to the tech's attention and inquire, make sure they check the terminations and draft. Then follow recommendations from the technician.

Re: Furnace Closet Ventilation

I agree, Chicken Little, that the vents should extend to the outside so as to prevent the potential buildup of gases in the attic. But I think the exhaust flue is implied.

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