Chimney Liner: Stainless Steel vs. Aluminum


The chimney plays a crucial role in the safe functioning of a fireplace or stove. It permits proper ventilation of toxic flue gases out of the home and helps keep the fire lit by creating a steady draft. Less well known than the chimney, but just as important, is the liner inside of it. Chimney liners serve a few key functions and can be made out of stainless steel or aluminum depending on the type of fireplace.

Metal Chimney Liner - Aurora ILThe first major responsibility of a chimney liner is to shield the combustible materials inside the house from the heat of the fire and smoke. Tests done by the National Bureau of Standards determined that combustibles adjacent to an unlined chimney can catch fire in as little as 3 ½ hours. Without a liner, the acidic nature of smoke and soot can also do damage to the chimney itself. The acid erodes masonry materials like brick and mortar, degrading the strength of the chimney and permitting the leak of toxic gases into the home.

Another function of a chimney liner is to create proper draft through the fire. The draft, or flow of air, travels from inside the home, through the fire, and up the chimney. Essentially, this flow keeps the fire fueled with oxygen and directs smoke out of the house, making a good draft vital. The width of the chimney plays a role in the strength of the draft, as a wide chimney gives the hot air more space to spread and cool, slowing its upward movement. Thus, having a chimney liner more fitting to the smaller size of the fireplace can quicken the upward air movement, starting a strong draft in the correct direction.

The main consideration when choosing a chimney liner is the material it is made out of. Modern chimney liners often come in stainless steel or aluminum materials, each of which have very specific purposes. Stainless steel liners cost more than aluminum, which may turn off some homeowners, but they must be used in chimneys venting fires that burn wood, coal, or pellets. The durable metal alloy can withstand the high temperatures created by burning solid fuels. It also resists the acidic corrosion from the by-products. Aluminum, on the other hand, is ideal for venting fires that burn natural gas. The cheaper, lighter nature of aluminum makes it easy to install and cost effective and it can hold up well to the lower temperatures of a gas-fueled fire.

Chimney liners play a crucial role in keeping the chimney functioning safely, making them absolutely necessary in every chimney. Beyond that, the material used to line the chimney also makes a difference. Choosing correctly between stainless steel and aluminum makes a big difference in safety and longevity of the liner. If your chimney liner is damaged or missing, talk to a chimney specialist about the best liner to have installed. For a specialist in the Aurora, Illinois area, contact Pozzi Chimney Sweep.