Howdy all. I am new to the site but not to burning wood. I currently have a Fisher Grandma Bear that heats my garage and a Lilly add on in the house. I will be moving shortly into one of my rentals as I am selling the current home. I have a central masonry chimney in the "new" house. My question is looking at liners it appears some are nothing more than a one piece flex pipe. So is there a reason you can't just drop several pieces of single wall pipe in and achieve the same effect? I plan to install the Fisher in the basement attached to the masonry chimney and expect to have to install a liner of some sort. Although I haven't inspected the chimney yet to see if it is workable or not. Just trying to do some homework. So I guess what I am saying is: School me on liners.