Direct vent through wall or roof?
We are planning on installing a direct vent propane heater as a backup emergency heat source, and to provide toasty radiant heat in our living room on extra cold evenings. I’m trying to reduce roof penetrations, so I had planned to direct the exhaust pipe through the nearby exterior wall.
But I’m just now wondering if venting exhaust through the wall might send too much moisture up into the attic through the vented soffit above. Propane exhaust contains a lot of moisture, which is one reason why using unvented heaters inside a home can be a bad idea.
Our exhaust vent will be about 4-5 feet below the vented soffit. Does anyone know if that is far enough away to prevent the moisture from being sucked up into the attic? I’ve seen a lot of photos of mold covering attic sheathing from humid bathroom exhaust air behind sucked into the soffits, and I’d like to prevent that in our own home. I’m in climate zone 4A in Virginia.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part