I installed my Woodstock Progress in December 2011 and had some performance issues especially at temperatures above 50 F. The flue was a 16 foot tall singe wall exterior uninsulated rigid liner up a 13x13 clay liner (fireplace installation). I removed the smoke baffle above the stove's loading door. Last year I had these issues at temperatures above 50F: 1. Difficulty starting and maintaining a fire. It tended to smolder and self-extinguish unless pampered and fanned. 2. Smoke spilled from the door while loading with an established fire - it was virtually impossible to open the door without spillage. Yea, I know, I removed the annoying baffle. 3. The stovetop temperature directly above the combustor would not climb much above 325 degrees after bypassing - The cat frequently stalled and I had to heat the stovetop well above 300F to get lightoff. 4. Gray smoke spilled from chimney.These problems diminished as the outdoor temperature dropped below 40 degrees, but I still experienced sluggish combustor light-off and difficulty reloading the stove without smoke spillage. After insulating (2 layers of 1/2" Olympias Super Wrap), with outdoor temps above 50F: 1. Stove lights on the first attempt with zero pampering. 2. Very little smoke exits from the door while loading, in fact the flame visibly gets sucked into the far side of the screen. (Annoying baffle still removed). 3. The cat lights off every time (engage at stovetop 250F) , stovetop temp climbs and no smoke outside. 4. I recently noticed my glass is staying crystal clear! My draft was just not good enough without insulation. The shorter flue did not help matters. I still have not burned at temps below 40 degrees, but things should only get better from here. Needless to say I am very happy I insulated this liner. The Progress Burns great now!