Most non-catalytic wood stoves have baffles to promote complete combustion of creosote and extract every last ounce of heat from your firewood before sending the stove’s exhaust up the chimney. Constant exposure to very high temperatures and corrosive gases from the fire causes wood stove baffles to fail sooner or later. When then happens, you’ll have to take on the chore of wood stove baffle replacement.
Make baffle inspection part of your wood stove maintenance routine. If your stove is in constant use, or you burn a lot of green firewood, you’ll be cleaning your chimney once a month. Take this opportunity to let the fire go out so the stove can cool down. While it’s cold, inspect the stove baffle for cracks and warping. Get to know the construction of your particular stove’s baffle system so you don’t have to learn it on the fly when the baffle fails.
Typical wood stove baffle construction consists of a large plate suspended in place somewhere above the flame. The baffle can be made of cast iron, stainless steel, or occasionally a fireproof synthetic fiber. It works by diverting the exhaust from the fire into a secondary chamber, where the trapped heat raises temperatures high enough to burn off much of the creosote in the smoke. This secondary burn chamber also sends additional heat into your home. Stoves with baffles are much more efficient than ones without them.
Just about all baffles are factory replacement parts. If you have a manual for your wood stove, looking up the replacement part number is easy, and frequently the manufacturer will include a diagram that will help you figure out the steps for replacing it. If you don’t have a manual, then the manufacturer’s web site might have diagrams and part numbers. If that doesn’t work, call or visit a dealer for your brand and get some help with identifying the part and finding out how much a replacement costs. $150 is a frequently quoted number for baffle replacements on popular brands of wood stoves.
Removing the baffle is going to be a frustrating job, because the mounting screws holding it in place are probably fused to their sockets from corrosion and high heat. Drilling them out after the bolts break would be a straightforward job if it were easy to get to them, but you’ll be working inside a small chamber with limited room to hold your tools.
When you’re ready to start the job, put quilts down on the floor to protect both the floor and the stove’s finish, or take the stove out to your shop and work there. Clean out the stove down to bare bricks so you can tip it at the best angle to reach the baffle mounts without making a big mess. If the bricks aren’t fastened down, remove them and set them aside to they don’t break when you start tipping the stove. Remove the door and any other parts that could come loose while you’re working. Plan to get dirty while you do this job.
One word of caution: many wood stove baffles have a ceramic fiber blanket fused to the metal plate. The fibers can hurt you if you inhale them, so manufacturers recommend that you not try to work on these stoves yourself. You can find out whether your stove is one of these models by consulting your owner’s manual, or by contacting a dealer or the manufacturer. If you insist on replacing one of these baffles yourself, treat this stuff the same way you would asbestos. That means full body protection and an industrial-quality respiratory mask.