Pulling this question from a larger post, hoping to get broader perspectives on this specific issue. I'm building an alcove for a Green Mountain 60 and need to figure out the best way to vent a heat trap at the top. I framed a new 3.5" wall in front of the existing load bearing wall so I can accommodate different ducting/venting configurations. I'm trying to prioritize safety and performance without compromising my wife's aesthetics. I'd welcome any input on the options below.
![[Hearth.com] Passive venting an alcove heat trap?](https://www.hearth.com/talk/data/attachments/344/344937-9077073e53af2828a8c10239bb5e9d1f.jpg?hash=Sg03eMAp6b "[Hearth.com] Passive venting an alcove heat trap?")
Option 1 (strip vent immediately above mantel) seems like the simplest and most direct, but also the least desirable. I currently have the wall framed for this option so I could simply cut the lower drywall off to open up the vent and fire the stove.
Option 2 (side vent) with the vent(s) to the side is the preferred approach. The question seems to be how well the air would flow laterally (up to 8ft from far end to the vent). It would be nice to only put in one larger vent, but we could put one on each end if necessary. Also unclear is how large the vent(s) should be.
Option 3 (strip vent at ceiling) would also be fairly simple but less desirable aesthetically. I also wonder how much placing the vent right at ceiling level would dampen the air flow - even though it would have the greatest chimney effect.
FWIW there will be passive ceiling vents just beyond each of the two ceiling beams. These will vent to two bedrooms on the second floor but may not always be open.
The air space behind the mantel is 12" high and about 9cf. The mantel is 57.5" above the hearth. GM60 (30" tall) requires minimum 61.5" alcove height, so I'll have a heat shield beneath and behind the mantel. Apart from the wood posts and mantel, all wall materials from surface to exterior block are noncombustible.
![[Hearth.com] Passive venting an alcove heat trap?](https://www.hearth.com/talk/data/attachments/344/344938-9b74e0b7ba3a7af684a552273f218a72.jpg?hash=WbnyhsXbbs "[Hearth.com] Passive venting an alcove heat trap?")
![[Hearth.com] Passive venting an alcove heat trap?](https://www.hearth.com/talk/data/attachments/344/344939-0256e3ae8d32430bd65bba144b987e20.jpg?hash=r8D8egt9rt "[Hearth.com] Passive venting an alcove heat trap?")
![[Hearth.com] Passive venting an alcove heat trap?](https://www.hearth.com/talk/data/attachments/344/344940-8f73c76d72ac26f166cf2cd9a9c0e838.jpg?hash=5e6IYs0_ll "[Hearth.com] Passive venting an alcove heat trap?")
![[Hearth.com] Passive venting an alcove heat trap?](https://www.hearth.com/talk/data/attachments/344/344941-1533ce549abb85e1ed484cf5e6b4d15b.jpg?hash=rxSSavGbHc "[Hearth.com] Passive venting an alcove heat trap?")
Option 1 (strip vent immediately above mantel) seems like the simplest and most direct, but also the least desirable. I currently have the wall framed for this option so I could simply cut the lower drywall off to open up the vent and fire the stove.
Option 2 (side vent) with the vent(s) to the side is the preferred approach. The question seems to be how well the air would flow laterally (up to 8ft from far end to the vent). It would be nice to only put in one larger vent, but we could put one on each end if necessary. Also unclear is how large the vent(s) should be.
Option 3 (strip vent at ceiling) would also be fairly simple but less desirable aesthetically. I also wonder how much placing the vent right at ceiling level would dampen the air flow - even though it would have the greatest chimney effect.
FWIW there will be passive ceiling vents just beyond each of the two ceiling beams. These will vent to two bedrooms on the second floor but may not always be open.
The air space behind the mantel is 12" high and about 9cf. The mantel is 57.5" above the hearth. GM60 (30" tall) requires minimum 61.5" alcove height, so I'll have a heat shield beneath and behind the mantel. Apart from the wood posts and mantel, all wall materials from surface to exterior block are noncombustible.
