Height of Horizontal Furnace in Crawlspace

How high should horizontal furnace be installed off the floor of a crawlspace? Again THANKS !!! for all your help.

Very unusual to find one in Ok installed in a crawl seen perhaps two but an unusual crawl lots of head room. The AHJ in this area requires 6 inches of clearance for any air distribution component and or distribution ducting perhaps different for you.

Thanks! Very unusual in the part of the world also. House built in 1950.


In my area, a Horiz.furnace must be at least (8"-clear) above ground, and unless I have remembered incorrectly, must have 12" clearance above the casing, to any combustible material(s).
Crawl spaces are still a viable design for HomeBuilders in our area. Not as many as there use to be years ago, but still out there.

Thanks! Greg