If your fireplace has poor draft, it can make your home smell like smoke while also creating an inefficient and messy burning environment. A poorly drafting fireplace burns wood inefficiently, releases smoke with little heat into the room, and sends incompletely combusted gases up the flue. These gases can leave behind layers of soot and creosote each time you build a fire. Installing a flexible stainless steel chimney liner inside your flue may help resolve these problems. A flexible liner is installed by inserting an insulated length of corrugated stainless steel into the existing flue. The liner is fitted to a connection above the firebox and suspended at the top of the chimney with a fitting that seals the space between the outside of the round liner and the inside of the square flue. This space can be filled with additional insulating material or left as dead air, which also provides some insulation.
A flexible stainless steel chimney liner can improve the performance of your fireplace and chimney in several ways. It makes the flue easier to maintain for two main reasons. First, less soot and creosote accumulate inside the liner, and second, a round flue is easier to clean than a square one. Because the liner helps insulate the flue from the surrounding chimney structure, combustion gases remain hotter as they travel upward instead of cooling as quickly as they would in an uninsulated flue. This reduces condensation of water, creosote, and corrosive combustion compounds because the flue gases remain warmer as they exit the chimney. A round flue is also easier to clean because it has no corners where buildup can collect. In addition, the expansion and contraction of the corrugated liner as it heats and cools can help prevent creosote from adhering as tightly to the inner walls.
Provided its inside diameter is properly sized for the fireplace it serves, a flexible chimney liner can improve the fireplace's drafting ability. The round cross-section allows combustion gases to flow more smoothly than through a square flue, where gases can become trapped in eddies and dead-air spaces. The insulated liner also helps keep the gases hotter, which can further improve draft because warmer air rises more quickly than cooler air. The result can be a cleaner, more efficient, and better-performing fireplace and chimney system.