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Heating, Air Conditioning, Fridge, HVAC/encapsulating crawl space with gas furnace


We have a 2400 sq ft 1 and 1/2 story home with split system of outside 5 ton A/C and gas furnace in our crawl space (which is about 3' tall.)  Due to moisture issues in crawl (some fungus and stringy insulation) one option that we are looking at is encapsulating the crawl where they come in and put heavy plastic in floors and walls as well as footings which seals off the vents and the object is to enclose the crawl so it is a self enclosed space.(with resulting minimum venting)  I asked about the gas furnace in the crawl and they said no problem a HVAC company could just pipe in air from the outside by running a PVC pipe similar to the current flue exhaust pipe present now.  However since these are not HVAC persons my concern is if this is feasible and the other concern is with carbon monoxide,   the encapsulating company claims it would be better from a HVAC standpoint as the crawl now be enclosed which would result in less heat loss and lower gas bills for the existing furnace.
Again, my concern is getting an opinion from a HVAC standpoint whether encapsulating a crawl space with an existing gas furnace and piping in air is or is not a good idea

The furnace needs combustion air if you have a high efficiency furnace you most likely can duct/pipe in the combustion air from the outside. I don't have any specks on your furnace but there are certain guidelines you have to follow in regards to bends, turns, distance of the combustion air inlet.

Heating, Air Conditioning, Fridge, HVAC

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Jim Barnhart


Fifty + years conditioning the air.


Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

Hands on since 1950

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