Question: I have a question. We are about to have a new pellet fireplace insert installed this week. We have chosen a Breckwell P24I. The dealer who will be doing the installation tells us all he needs to do is attach the insert to a 5 foot chimney and insert the unit into the fireplace. He says this will vent properly up the existing chimney, which is 18 feet tall. My concern is will this cause any condensation in the old chimney? I would feel better if the new metal chimney was going all the way up the old chimney. What are your thoughts on this? Answer: The installation that the installer mentions may not meet the specs in the Pellet Stove owners manual which usually states that a lining to the top of the flue is needed. However, I have seen many installations done with only a 5-6 foot tube and in most cases they worked well. In all cases a sheet metal block off plate has to be tightly fit into the area below the damper and sealed well around the pipe. Condensation is a strange thing...it depends on a lot of factors like climate, weather, locations of chimney, etc. You should ask about a price for a total reline and also view the manual to see what the manufacturer has to say.