I recently modified my Mama Bear to a top exit chimney style. This eliminated the funky adapter that was originally on the back and made the stove a little more compact from the space savings of not having a rear pipe. I installed a damper in the pipe as well. The stove still draws well and I have no problem at all keeping a fire overnight. In a 1478 square foot home we have to open the doors at times. I am very happy with the mod and it really does work well. I also welded two small pieces of angle to the back in case I needed a steel heat shield but have not found it necessary.