Originally Posted by
Jerry Peck
The IRC implies, based on the drawings, that when obtaining combustion air from a crawlspace that the lower opening is allowed to vent from the ventilated crawlspace, but that the upper opening is to be vented out through the attic - Figure G2407.6.1(1).
Any comments on the crawl space vents being blocked during the cold months.... which, of course, is when the furnace is going to be used?
Up here in 'crawl space land' the design throughout the 80's was to insulate the perimeter walls and leave notes on panel box and furance that instruct the homeowner to block the foundation vents during the winter. On houses after the underfloor insulation requirement in the early 90's I typically tell my clients it's not of as much importance to block the vents.