Flue liners fail to function, and they have to be relined for safety and to function appropriately. Stainless steel liners do not deteriorate as fast as other flue liners and, therefore, are highly recommended.
Metallic flue liners like stainless steel are the best and recommended by fire-protection professionals. Most installers prefer them even if they are the most expensive compared to clay tile and cement cast-in place liners. The liners are suitable whether the fire is due to wood burning, oil, or gas.
There is an excessive buildup of creosote and production of deadly and odorless carbon monoxide in flues without liners.
A flue liner ensures that heat and fire do not get to the explosive components around to avoid accidents.