I added 2 ft to my chimney(class A) and it sure seems to make a big difference in the Liberty. Much better draft so that now I can damper down completely at night and still have coals and heat in the morning. The glass is not completely black either. That Liberty sure is easy to light, it just takes off. I have only had a couple of fires, I just started one this am to take the chill out of the house.
Doug
Doug