A local fellow is selling a Wood Marc wood burning insert. I am looking for a fairly cheap way to keep my ridiculously high gas bill down in the coming months. I have a friend who is an arborist and with that, I have all the wood I can split. I have seen photos and cosmetically, this thing seems to be in great shape...seldom used. While speaking to him on the phone, I learned that I do not need a chimney liner or stove pipe (my masonary chimney was recently inspected and found to be in good shape). Am I understanding this right? This thing just shoves into the opening, gets insulation packed around it and the cover put over the stove/opening? Sounds shady to me, but I am just a dumb carpenter. If someone can shed some light on my situation and let me know if these inserts are safe/efficient I would greatly appreciate it. Thanks, Bruce