Hi GBA,
I’m preparing to install a pellet stove through an existing fireplace. The 3″ and 4″ duravent pipe will exhaust up the chimney. The pellet stove manual calls for a fresh air intake. Running the fresh air intake up the chimney is doable but not as easy as it sounds. The 2″ and 3″ fresh air pipe would require a u-turn at the edge of the chimney cap to avoid pulling in the exhaust air. This would be approx. 16′ tall and pulling cold air downwards might be difficult.

After recently discovering a pocket/cavity inside the wall I considered the idea of pulling fresh air from the vented attic space. This would allow a shorter run of less than half the length, approx. 8′ of vertical run and avoid any potential problems near the exhaust pipe.

I like this idea because if the pellet stove were removed the only hole requiring patching would be at the drywall, not a hole through the brick or masonry.

Are there any obvious or code related reasons not to do so? I’m located in Massachusetts.