Do I Need a Chimney Liner? All About Chimney Flue Liners

Time after time, chimney maintenance is neglected and chimneys only get serviced once an issue has occurred. When the heating season begins, you may question the quality and performance of your chimney. It may have been brought to your attention that a stainless steel chimney liner should be installed to safely and efficiently vent your heating appliances. Installing a chimney liner can easily be accomplished by any do-it-yourself homeowner.


Generally, a chimney fire happens when the flue has been neglected and an abundance of creosote has built up on the walls of the chimney. After a chimney fire has occurred, terra cotta flue tiles are very susceptible to cracks. The slightest hairline crack can cause creosote and carbon monoxide to leak through the chimney. If a crack is found in the terra cotta flue, it is important to reline the chimney before the next fire. A stainless steel chimney liner is water and air tight, ensuring no creosote leakage. Stainless steel chimney liners can handle multiple chimney fires over 2000 degrees. The smallest crack may not look like much harm, but it is hazardous the home and household.

In addition to clay tile cracks, missing mortar joints can allow creosote and carbon monoxide to leak through the chimney. Mortar joints deteriorate when natural gas and oil fuel emissions cool down rapidly and produce condensation. Over a period of time, the acids from condensation eat away at the mortar joints, causing them to be obsolete. The condensation can also cause water damage to the home. If you notice water entering the chimney, and the chimney rain cap is in good condition, it is most likely from flue gas condensation. Using a stainless steel chimney liner to shrink the size of the flue will keep the flue gasses hotter and will eliminate the condensation.

Overall, chimney liners increase safety by:

  • Reducing chance of chimney fire
  • Reducing risk of carbon dioxide leak
  • Reducing chance of water damage


Clay terra cotta chimney flues are often far too large for the specifications of the appliance. They are also poorly insulated, which causes inadequate draft for the appliance. Newer and more efficient heating appliances require a much smaller venting size. If the current flue size is 2 to 3 times larger than the recommended area of the vent, the appliance is not going to run to the specifications that are advertised. The added stress on the heating appliance is going to use more fuel, making the high efficient appliance less efficient. The more area there is in the flue, the longer it will take the flue to heat up to induce the draft. Using a stainless steel chimney liner will reduce the flue size to the manufacturer's specifications, improving the efficiency of the appliance.

Overall, chimney liners increase efficiency by:

  • Maintaining optimal air flow
  • Reducing the amount of fuel needed
  • Inducing the proper draft

Installing a flexible, stainless steel chimney liner to vent your heating appliance is a smart choice to protect your home from harsh emissions and give you peace of mind. To learn more regarding chimney liners, please read our other articles located under Articles & Info. If you have any questions, feel free to contact us toll-free at 866-708-2446.

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Our 316Ti flexible chimney liner and chimney liner components have passed the rigorous testing at the Underwriters Laboratories with best in class status and are UL Listed. So if you are looking for UL listed chimney liner sold directly to homeowners, then look no further than Rockford Chimney

Customer Testimonials

Back in July you gave me excellent advice re. sizing/purchasing a flue liner for the chimney associated with my wood stove. I'd like to thank you once agai... More

—AE Northfield, MN

A few weeks ago I ordered a chimney liner system for my fireplace insert. Your salesman recommended the liner system plus the insulating blanket. I just wa... More

—AH Happy customer

Just got around to installing my new smooth flexible liner and deluxe terra cotta cap (wow). The quality of your product is second to none. Very pleased an... More

—B.B. from Massachusetts

Thanks so much for the great tech service from Dennis, very knowledgable, friendly and proffessional.Your website is the best, beats your competition by fa... More

—Bill in Knoxville

Sue and Dennis, I received the final part of my order yesterday (the chimney cap that actually fits over the chimney chase). It looks wonderfu... More


Hello, I was shopping for an fireplace insert and called RCS to ask why they were so much cheaper than my local guy, the reply was " we sell thousand of th... More

—Chris, PA.