i am going to be building a new heart thing for my pellet stove in my living room, what is going to be the best pipe to use? the pipe is going to be all enclosed. also go 3 or 4 inch? also have not decided if i am going out the wall or the roof. out the wall would be going up and over the stairwell to the basement. only reason for wanting to go the wall way is i have a funny roof line straight up from where i want to go out. ( the roof line from my porch ties into the reg roof) i can post pictures later if needed.