I was referred to this site by a local Quadra-Fire dealer. My wife and I are very interested in installing the 7100FP but have come across a potential show-stopper. We are planning on demolishing our interior brick facade and modify the existing fireplace to accept the 7100FP. The existing chimney resides outside of our house and has a ceramic flue liner which measures 9 x 13 inches. The problem is with the 9" width and the interference with the SL-300 or Dura Pipe, both of which have external diameters greater than 10". I can demo the liner which would give adequate clearance for either pipe. However, I'm concerned about the condensation effects. The pipe would be ascending a non-ventilated chimmeny, the exterior of which is exposed to the environment. Though I don't believe we'd be hearing the "hiss" of condensate dripping down onto a hot surface, there is the real potential of the pipe rusting out in a few years. If anyone has had a similar installation or would like to share thoughts, we're all eyes and ears hear in Colorado.