I've recently been looking into wood burning stoves. Many installations use a stove pipe that goes straight up through the ceiling and out the roof. Most of these use a single walled pipe for the first room (the room containing the stove), and then through the second floor and attic/roof sections a double-wall insulated pipe is used.
My question is, for what reason is a single walled pipe not used for the second floor room? Surely this would allow more of the stove pipe heat to be used to heat the upper floor? (note I mean the upper room, not the attic section).
The only possible reasons I can see are:
Fire hazzard. But in this case couldn't a protective guard be placed around the pipe, to stop anything touching it?
Increased creosote build up. But we're not talking about a massive temperature difference here - so would this really have such a bad effect?