Do mechanical rooms with gas appliances always need combustion air? The furnace is high efficiency but the water heater is gas as well. There is no dedicated combustion air supply and the room is vented from and into the adjacent office room. Mechanical room is in a basement. Is this correct or is it a health and safety issue. The local code says its ok. This is in Greeley Colorado.
Do you know this for fact, or is it what a local “expert” told you?
If ‘fact’, what is your source for this determination?
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Yes, but not always from the exterior. Think of how many basements you have been in where combustion air is supplied from the surrounding area.
Code on on this subject will vary greatly as well as manufacturer installation instructions.
Combustion air may not be provided via an adjacent sleeping room, that’s pretty universal.
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True i cant verify. He teaches code but is an HVAC technician. He did provide a general reference to the IRC but not the specific section. My concern was the open vents to the livable spaces of the home.
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Thanks. Im honestly still not sure…i suppose the concern would be gases entering the livable spaces of the home.
You can state your concerns in the report. Code doesn’t matter.
You can also look up the installation instructions provided for the model number of the appliance.
It is not unusual to find natural draft gas water heaters in mechanical closets, laundry rooms, basements etc. Each manufacturer will have a guide to fresh air makeup and exhaust.
I have spent many hours reading install instructions in situations just as yours out of concern for safety.
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It works the other way. For every cubic foot of natural gas burned, at least 16 cubic feet of gas goes up the chimney. The extra 15 cubic feet comes from somewhere: the heated office, a closet, cracks, the crawl space, whatever.
It sucks, not blows.
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Thanks for the honesty.
Your reply speaks to why you should never make such a statement in your report or to your client, that you haven’t verified to be true. Trust no one, not even me, unless you are satisfied of the quality of the answer enough to place your and your companies good names at risk!
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I recently inspected a 2 story track home in So Cal where venting the furnace closet might have been a bit overboard. The door had large vents that should have been enough but someone felt otherwise I guess.
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What was it’s age? That system screams 60s-70s to me, and furnaces back then were literal pigs for needed venting! Those louvers in the door were barely minimal at best.
(Yes, I lived in SoCal late 70’s to late 80’s).
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It does look old. But to their credit, the design looks solid.
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Agree. I would trust that system over the louvered doors anyday!
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House was built in 1979 but the furnace was replaced with a Goodman in 2013. I’m sure it had an old pig of a furnace before. It was vented on the inside of the closet as well, through the floor joists, but the exterior vent was covered up by a ledger board for a patio cover. So the added vents were probably a good idea.