We recently purchased a Regency CI2600 with a non insulated flue liner from a dealer. We had it installed by our contractor who had to rebuild our fireplace. He suggested that we put insulation around the flue where the liner goes up into the chimney. What kind of insulation do we need to purchase for this. I have read many threads here and see that many suggested that the flue liner should have already been insulated, but that is not what the dealer sold us, so I am trying to figure out our options. We have not had a wood insert before so we are unfamiliar on what to do. Thank you for your time.