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What the heck is a chimney liner, and why do I need one?


Most likely, chimney maintenance isn't something that crosses your mind frequently -- if ever! -- but it is surprisingly important to the overall safety, integrity, and efficiency of your home and something to keep in mind when completing your annual home maintenance checklist.

So, what exactly is a chimney liner?

Although it seems obvious, the first and most important thing to know about your chimney is that it exists solely to carry heat and dangerous gasses (from the fireplace) out of your home. In other words, it allows you to safely enjoy that cozy Winter fire that you love so much. A chimney liner sits between the walls of the chimney and the flue, creating a barrier of protection for the chimney and allowing it to safely escort the gasses created by the fire to the outside atmosphere.

Why do I need a chimney liner?

The primary reason for all homes to have a chimney liner is -- you guessed it -- safety! A liner keeps the temperature inside the chimney down, therefore lessening the risk of a chimney fire. It also keeps dangerous gasses, such as carbon monoxide, from leaking into your home. Due to better air flow and heat retention, a liner increases the energy efficiency of your chimney and home. As a result, a lined chimney requires less wood and/or fuel to heat an area of your home.

What type of chimney liner is best?

Currently, there are three types of chimney liners on the market: Clay Liners, Cast-in-Place Liners, and Metal Flue Liners.

Clay Liners were traditionally most popular, because they are made of relatively inexpensive materials, clay is virtually impenetrable by heat and fireplace gasses, they require very little to no maintenance, and they last a long time. Unfortunately, though, due to their square shape, these liners are not highly efficient. Smoke travels up and out of a chimney in a spiral pattern, so Clay Liners have many unused pockets of space. Another disadvantage to these liners is that they are somewhat difficult to install, which translates into more money out of your pocket.

Cast-in-Place Liners are created with a poured concrete process and are generally used when there is damage to the masonry inside of the current chimney and a Clay Liner is not an option. Cast-in-Place Liners offer all of the benefits of Clay Liners. Additionally, because of their great insulation properties, they tend to run hotter and reduce the accumulation of creosote within the chimney. These liners last at least as long as Clay Liners and are similarly somewhat difficult to install and repair.

Metal Flue Liners are most commonly used in new construction today. They are pre-made and come in many different shapes and sizes. Generally speaking, Metal Flue Liners are made out of stainless steel or aluminum. A primary advantage of these liners is that they are much easier to install than Clay Liners. If installed properly, they are very efficient and can last a long time.

In order to preserve the safety, efficiency, and integrity of your chimney AND home, it is best (for you or a reputable chimney service company) to routinely check for structural damage or other problems with your chimney and its liner. Although your fireplace and chimney is probably far from your mind now as Summer approaches, you will be grateful when you hunker down for a warm, cozy fire in December!


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