Baffles and brick insulate the stove to keep heat where it belongs – in the firebox. This protects the outer components of the stove, improve efficiency and heat output even on longer, lower burn settings.
What is firebrick?
A layer of bricks in a stove or fireplace helps to insulate the stove and deflect heat back into the firebox. This ensures an efficient burn and protects the metal body components from warping & heat damage. These bricks come in a variety of sizes and shapes to fit the precise dimensions of the firebox. The most common size is a 4-1/2” wide by 9” high rectangle that is usually about 1-1/4” thick. Sometimes stove manufacturers will create ceramic panels that match the contours of the firebox rather than individual brick.
What is a baffle?
A baffle deflects heat inside the firebox to protect the top of the stove from extreme heat, traps flue gasses for secondary combustion and then helps to channel the smoke toward the flue. This increases the heat output of the stove and reduces particle emissions. A baffle can be made from steel, cast ceramic, or ceramic fiberboard. Baffles come in all different shapes and sizes, so it is crucial to know the exact stove model when ordering a replacement.
How to prevent damage:
Most stove brands do not offer warranty coverage on baffles or firebrick beyond safe arrival. This is because a variety of factors such as frequency of use, operation conditions, and maintenance habits will impact the lifespan of these parts. Here are 5 steps to protect and preserve the brick and baffle(s) in your stove or fireplace:
1. Clean & Inspect the Chimney
Creosote in the chimney restricts air circulation and could allow firebrick and baffles to overheat. This makes them much more likely to crack, crumble, or deteriorate sooner. Start with a clean chimney each fall and check it once a month during the peak heating season.
How to inspect your flue:
Place a mirror at the base of the chimney and angle it to look up the flue. Creosote build-up will restrict the flow of air in the chimney and not allow as much light to pass through. If you notice the chimney seems narrower at the top, then it is time to clean the flue.
2. Keep the Firebox Clean
Regular, meticulous cleaning is one huge step in extending the lifespan of firebrick and baffles. Keeping the firebox clean helps the stove to burn efficiently and regulates the firebox temperatures better.
3. Follow Fuel Recommendations
Using firewood that exceeds the stove manufacturer recommendations or an oversized load of firewood can build up too much heat in the firebox which will increase the rate of deterioration for brick and baffles. Burning garbage or treated wood products also increases the probability of damage from excessive heat and produces more dangerous creosote than seasoned firewood.
4. Avoid Thermal Shock
Thermal shock occurs when brick and baffles are exposed to a dramatic or uneven change in temperature. Begin the heating season with 3 small, shorter fires to gradually build up to large, hotter fires. When lighting the stove on a cold day, be sure to gradually build up the heat in the firebox to give those bricks and baffles a chance to evenly distribute the temperature change.
5. Monitor Operation with a Thermometer
Monitoring the stove temperature while in operation with a magnetic stove thermometer (such as this one HERE) allows you to adjust stove settings before extreme heat can build up and compromise the brick and baffles lining the firebox. Introducing more air will increase the heat level while less air will reduce the heat. Refer to the owner’s manual for your stove for a recommendation on the best temperature range for an efficient burn at your desired setting.
When to replace:
Over time the prolonged exposure to extreme heat in the firebox will eventually deteriorate firebrick and baffles, even under normal use and perfect maintenance. If you start to notice large cracks and crumbling pieces, then the brick or baffle should be replaced. Continuing to use the stove with missing or damaged brick or baffle will allow too much heat to escape the firebox because that insulating layer of protection is compromised. This will result in inefficient fires that do not produce as much heat and leave the body components vulnerable to warping and heat damage.