Your chimney liner is one of several important components that work together as part of your home’s fuel-burning and venting system.
These components include:
- The fuel-burning appliance, such as a fireplace, woodstove, oil- or gas-burning furnace, or a combination of appliances venting through a single chimney
- The chimney flue
- The chimney liner
- The chimney structure
- Controlling features such as dampers, fans, and thermostats
- External features such as chimney caps or top-sealing dampers
When all of these components are properly sized and work together as intended, your home can remain safer while your fuel-burning appliances operate efficiently. If one or more components are improperly sized or configured, you may experience poor chimney draft, inefficient combustion, or the backflow of smoke and combustion gases into your home.
If your chimney liner is made from the appropriate material and properly sized, it can improve the venting of combustion gases from your fireplace, woodstove, or furnace. Your appliance manufacturer can provide guidance on the appropriate liner diameter for your specific appliance and venting requirements.
A chimney liner that is too narrow for the appliance it serves may not be able to carry smoke and other combustion products upward efficiently. This can contribute to inefficient fuel burning, the accumulation of creosote and moisture inside the liner, and the potential leakage of combustion gases into your home. Conversely, a liner that is too large may also interfere with proper venting because it may not become warm enough from bottom to top to establish a strong, consistent updraft.
Insulation can have a significant impact on how effectively a chimney liner vents combustion gases. If your chimney is located along an exterior wall of your home, the chimney liner should generally be insulated from top to bottom. If your chimney is completely surrounded by conditioned, insulated areas, you should still consider having your chimney liner insulated through any portion of the chimney that extends into an uninsulated attic or above the roof line.
Proper liner insulation helps keep combustion gases hot as they travel up the chimney and exit your home. This can reduce the potential for downdrafts caused by cooler gases near the top of the chimney while supporting a stronger upward flow that carries smoke and combustion gases outside. An insulated chimney liner can also help reduce creosote and ash buildup on the liner walls, which can interfere with smooth airflow by increasing resistance between the exhaust gases and the liner surface.
If your chimney liner is properly sized, correctly installed, and adequately insulated, it can help improve the venting of combustion gases from your home. Proper chimney draft is essential for directing smoke and combustion gases outdoors while helping reduce the accumulation of creosote and moisture inside the chimney.
If smoke backs up into your home while you are using a woodstove or fireplace, consult a chimney sweep or qualified chimney professional to determine how your venting system can be improved. The professional may recommend changes to how you operate your fireplace or woodstove, or may determine that a different chimney liner is needed to improve the system’s venting performance.