Well after reading and seeing so many coments about how exterior chimneys with un-insulated liners build up creoste faster due to the cooling of the efect of the masonry, I decided to douse the fire and do a cleaning. An hour after I extingused the fire I climbed up onto the roof all tools in hand, pulled the cap which had some build up making me afraid to look down the pipe, low and behold all the was was very fine soot no creosote (deep sigh of relef). I brushed the pipe out anyway since I was there. I have been burning questioable wood since that is all I have but I achive good coals and keep the stove from 500-600 most of the time. One thing I did notice was and please comment accordingly. Standing on the ladder and leaning on the chimney I was nice and toasty the masonry was warm which is what prompted this post. Brick and concrete once warmed retain heat for quite some time. I burn 24/7 so the chimney never realy gets a chance to cool down. I do however live in a pretty mild climate. Due to that fact and the fact that it rarely gets to 20d here do I realy need to inulate my liner? Would I see that much better performace and would it make a big diference in the whole performace of things? I just want to narow it all down before I spend $400-500 on insulating my liner. two houses ago we lived in a concrete block hous which had a walkway next to it. I remember on warm days after the sun had gone down walking by it he house and you could feel the heat radiating off of it for hours. Just a thought. Thanks!