Magus said:Well I took some measurements last night and this is what I found.
That doble wall pipe is gawd awful expensive.
And worth every penny!
I too investigated single versus double wall stove pipe, initially intending to go single for more heat and less cost. But, despite my frugal nature, I decided it was not the place to go for the cheaper solution.
A modern stove heats through the stove, not the stove pipe, and needs its cooler exhaust gasses kept as warm as possible to improve draft (stove performance) and keep the chimney clean (improving performance and prevent house-threatening chimney fires). In addition, it is safer and lasts longer.
It's a matter of one's own priorities, but for those who value stove performance and safety, double wall is the better path.