Although relining a fireplace, pellet stove, wood burner, or any other heating appliance can be relatively easy when instructions are followed, there are a few common misconceptions as to what is “safe” when it comes to chimney liners. For one, every appliance must be vented through a chimney. No liner can pass through walls, ceilings, floors, or windows, only a chimney. Also, a chimney cap should be used to cap every chimney, even the unused flue system, because a flue system is a perfect home for any number of small critters, their offspring, and whatever nesting material they introduce into the flue system. If possible, purchase a spark arresting cap.
Your flue liner should be the same size as the pipe extending through the top or back of your heating appliance. You should not try to downsize your flue system unless your chimney is extremely tall (30 ft. or higher) and even then it is still wise to simply go with the size recommended by the manufacturer.
Your floor and walls need protection as well! Make sure that the floor which the appliance is sitting on is either concrete slab, ceramic tile, marble, slate over UL Listed cement, or are UL approved mats or boards if you have a pre-fab. Look into wall protection. The walls within 36″ of your appliance need to be brick, stone, cement board, or UL approved stove shield (which are mounted to the walls using spacers.) These will protect your home further from heat transfer and fire.
Don’t wait until it’s too late! Putting off a chimney repair such as a reline can put the entire home at risk of fire damage. The cost of rebuilding an entire fireplace, exterior and interior, far surpasses the cost of installing a stainless steel liner. Not to mention the increased efficiency of your appliance is right around 15%, so the liner will pay for itself within a few years of lowered energy costs.
Finally, when purchasing a liner, especially on the internet, do not go merely by price. Look up customer reviews on a particular product and compare gauges of steel, the size of the liner, and check to make sure all components are included if purchasing a kit. It is important to realize that the cheapest liner is not always best, and not all liners are created equal. Check statistics such as crush test rates and be sure to read the fine print.