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Hello all,
Let me state that I’m a cabinet guy by trade. Now to the question. My home has the furnace in a hall way closet here in San Diego,Ca and there is an intake vent below the door. When the new furnace was installed by the previous owner they also cut a hole into the subfloor(into the crawlspace). I now have a direct path for cold air to enter the house via the hole and the intake vent(in the hallway under the door). I need to stop this airflow path but want to know which is the correct way, ie. intake from under the house or intake from inside the house. Or could it be that for this furnace it needs that much airflow and it needs both?
TIA, troy
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Tony:
You can find the basic requirements for your type of installation in the combustion air section of the mechanicals at:
codecheck
Use frames for easier navigating
*Is this a trick question? Cold air in San Diego? Post your address and in a couple of months I'll mail you some _real_ cold airRules for this are complex, best to (i) check with a local code person or HVAC contractor and (ii) after meeting the rules, have the flue checked for proper drafting. (The rules are theoretical, following them doesn't always work, in practice.)BTW, rule of thumb: 1 sg in _free_ vent space for every 1,000 BTU in the enclosure (e.g., 75,000 BTU furnace & 30,000 BTU water heater needs 105 sg in free vent space (typically codes call for 1/2 at te top and 1/2 at the bottom of the enclosure. It's the crawlspace part that makes it tricky.Bob
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Hello all,
Let me state that I'm a cabinet guy by trade. Now to the question. My home has the furnace in a hall way closet here in San Diego,Ca and there is an intake vent below the door. When the new furnace was installed by the previous owner they also cut a hole into the subfloor(into the crawlspace). I now have a direct path for cold air to enter the house via the hole and the intake vent(in the hallway under the door). I need to stop this airflow path but want to know which is the correct way, ie. intake from under the house or intake from inside the house. Or could it be that for this furnace it needs that much airflow and it needs both?
TIA, troy