Re: Furnace Room's Fresh Air Intake Comes From Attic
A portion of that air could be drawn into the furnace through the return air connection at the furnace.
Originally Posted by EricTheRon
This setup could contribute to increased negative pressure within the home and surely will ceate a negative pressure in the attic space which would upset the attic venting.
You can test this by checking the airflow through the vent both when the flame kicks on and when the fan kicks on--if the airflow is about the same then this is just a combustion air supply. If so, there's nothing wrong with this venting arrangement, assuming your attic does have vents to the outside like most do. However, I would extend that vent above the insulation to make sure it doesn't get covered, and I'd put a screen on both ends to stop bug migration (your attic vents should be screened anyway, but JIC!).
Also drawing fibers from the insulation down into the living space.... which is not a good thing.
The outside air is considered "fresh air" ... somehow I have a hard time believing this would be allowed.
Actually if this is just combustion air it isn't such a bad idea. Usually there's a vent direct to the freezing outside air, and pulling that in usually makes your crawl space or furnace room pretty cold. The attic should be warmer most of the time--and the air movement should help keep your attic insulation dry. (All this presumes that there isn't a fire danger related to this vertical vent.)
I'd be curious if this wouldn't violate a fire code since it is open from the basement to the attic.
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