JT, I made my own pipe for my owb. 4 3/4in pex lines inside with split foam pipe insulation on 3 of the pex lines, then wraped over all that, and put it all in a 4in sch40 pvc pipe. I buried it 3.5 to 4ft deep. Stove is right about 115ft away from where the pipe goes in the basement. This is my first season with the owb, so I really dont know how well it is going to hold up. But so far the coldest temp ive had here is 16f and I lost about 4.5 degress from owb to heat exchanger. I was happy with that. But still waiting on a good snow for a true test.