# Utility Room Ventilation



## jhicks (Dec 15, 2014)

I need some help from the HVAC Pros.
I'm a tile contractor and part of an upcoming job is to tile the utility room. 
This room has the furnace and the hot water heater in it. I noticed a vent on the floor and was told by the home owner that it just opens to the crawl space below. He says he was told it's the ventilation for the room due to the furnace being in there. 
Here's my question: Does that vent need to be there. If it doesn't the owner would like fill it in and tile it. 
I've attached a photo to see what's going on in there. Thanks!


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## overanalyze (Dec 28, 2010)

I would guess it is the fresh air intake. I wouldn't remove it. That is an older 80+ furnace. It gets its make-up air from that vent/hole.


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## beenthere (Mar 5, 2009)

Yep, its a combustion air intake for the furnace and water heater.


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## jhicks (Dec 15, 2014)

Alright, thanks guys. 
Since one of the walls in that room is the garage wall, can we pull that air from the garage in the form of a wall vent panel or does the source need to come from the exterior?


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## overanalyze (Dec 28, 2010)

You can't/shouldn't pull air from a garage. The fumes from a car aren't considered fresh air. Whats the duct in the ceiling?


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## jhicks (Dec 15, 2014)

Yeah, that's what I figured regarding the garage. 
I had asked the homeowner what that duct was and he said it simply stubs out in the attic. He said it has some cloth over it on the attic side. Is that usable for fresh air?


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## beenthere (Mar 5, 2009)

Code actually requires a high and low combustion air intake. And that is what those 2 are. Neither is fresh air, they are both combustion air. 

Many jurisdictions are allowing a single combustion air intake, but yours may not.


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## beenthere (Mar 5, 2009)

If using inside air, the source and the utility room must have a combined free air volume of 50 CF per 1,000 BTUs input rating, of the total number of gas burning appliances. So if you have an 80,000 BTU input gas furnace, and a 32,000 BTU input gas fired water heater. You have a total of 112,000 BTUs of input. And must have a free air volume of 112 times 50=5,600 CF.


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