A chimney liner serves as a protective barrier, preventing the escape of combustion byproducts and enhancing the overall performance of your furnace.
Whether you are upgrading an existing system or installing a new one, a properly installed chimney liner is essential for compliance with safety standards and building codes.
This guide will take you through the step-by-step process of installing a chimney liner for your gas furnace.
Putting in a Chimney Liner for Your Gas Furnace
A gas furnace is a reliable and efficient way to keep your home warm during the chilly months.
However, ensuring proper ventilation is crucial for the safety and performance of your heating system.
Installing a chimney liner is a key component of this process, as it helps to channel harmful gases out of your home while maintaining optimal airflow.
Materials Needed:
- Chimney liner kit
- Tape measure
- Screwdriver
- Tin snips
- Chimney brush
- Polyurethane foam sealant
- High-temperature silicone sealant
- Drill with masonry drill bits
- Ladder
- Safety gloves and goggles
Step 1: Measure Your Chimney
Before purchasing a chimney liner kit, measure the dimensions of your chimney to ensure you select the right size.
Measure the length and diameter of the flue, as well as the height of the chimney from the furnace to the top.
Step 2: Choose the Right Chimney Liner Kit
Select a high-quality chimney liner kit that suits the dimensions of your chimney. Kits typically include a flexible stainless-steel liner, connectors, and other necessary components. Ensure the kit meets local building codes and regulations.
Step 3: Prepare Your Work Area
Clear the area around your furnace and chimney. Place a drop cloth to protect the floor and nearby furniture. Wear safety gloves and goggles to protect yourself during the installation process.
Step 4: Remove the Old Liner (if applicable)
If there’s an existing liner, carefully remove it using a screwdriver and tin snips. Clean the chimney thoroughly with a chimney brush to remove any debris.
Step 5: Install the Bottom Connector
Attach the bottom connector to the gas furnace flue. Use a screwdriver to secure it tightly. Make sure the connection is sealed properly to prevent any gas leaks.
Step 6: Insert the Chimney Liner
Carefully feed the chimney liner down the chimney from the top. Have a helper assist you by guiding the liner and ensuring it doesn’t get stuck or twisted.
Step 7: Connect Sections and Seal Joints
As you lower the liner, connect additional sections as needed. Secure the connections with the provided clamps and screws. Apply high-temperature silicone sealant to the joints to ensure a gas-tight seal.
Step 8: Secure the Top Connector
Attach the top connector to the upper end of the chimney liner. Use screws to secure it in place, and again, apply sealant to ensure a secure and airtight connection.
Step 9: Insulate the Liner (Optional)
For added efficiency, consider insulating the chimney liner with an insulation sleeve. This helps to maintain optimal temperatures inside the liner and improves the overall performance of your gas furnace.
Step 10: Seal Gaps with Polyurethane Foam
Inspect the entire installation for any gaps or openings. Seal these areas with polyurethane foam sealant, paying attention to both the top and bottom connections.
Why do I Need Chimney Liners?
There are multiple purposes for a chimney in a home. There is still a time when they are used to ventilating a building in case of a fire, but their role is much more important than that.
Steam that is released from your furnace is vented through the chimney based on its efficiency. Steam can reach 700 degrees Fahrenheit from older, less efficient furnaces.
To escape from an opening in a chimney, this high heat needs the entire space. The chimney is also used for ventilation in more efficient furnaces, such as those at 80% efficiency.
Their steam is, however, dramatically reduced to 400 degrees Fahrenheit, so they do not require a chimney with a large cavity. The need for chimney liners arises in this situation.
Helpful Resource: https://www.lindemannchimneysupply.com/determining-fireplace-liner-sizing
The chimney liners line the inside of the chimney, as their name suggests. In order to fill up the chimney space, they reduce the size of the chimney space by making it smaller. Let’s take a look at why this is necessary.
Due to the fact that steam from furnaces with higher efficiency does not occupy all of the chimney space, moisture can build up. In this case, the mortar can become corroded, leading to acid seeping into the chimney.
Does A Gas Furnace Need A Chimney Liner?
Ask yourself a few questions to find out.
1. Which Type Of Furnace Do I Have?
Unless it is very old and inefficient, you probably do not need a liner. In high efficiency HVAC systems with 90% AFUE or higher, a chimney liner isn’t required because ventilation is separate from the chimney.
2. What Type Of Chimney Do I Have?
The metal chimney flues in newer homes are typically already small enough to accommodate higher efficiency furnaces.
Depending on how efficient your furnace is, you may need a chimney liner for an older house with a wide brick chimney.
3. Do I Already Have A Chimney Liner?
You can check by looking at the top of the brick chimney flue. There will most likely be another metal flue sticking out above the original brick opening if you have one.
Types Of Chimney Liners
Chimney liners fall into three main categories:
A clay tile liner (sometimes called a “terra cotta” liner) consists of fired clay tiles, usually about two feet long, which are stacked one on top of another and sealed with heat-resistant mortar. Typically, brick chimneys have these.
A cast-in-place liner is made out of similar materials to concrete that is pumped into the chimney in order to create a tunnel. Replacement liners like these are generally found in historic chimneys where additional structural strength is needed.
A metal liner is a liner made from stainless steel or aluminum. Most commonly, they are used to replace damaged or missing clay tile liners and are the most popular repair / upgrade option.
How Much Does it Cost to Install a Chimney Liner?
It usually costs about $1,800 to $2,500 to install a stainless-steel liner for a gas furnace, while $2,700 to $4,000 to install a stainless-steel liner for a fireplace.
Several factors affect the cost of the installation, including the type of roof and the slope of the roof, the flue’s curves, the size, and type of the liner, as well as the type of connector.
Maintaining Your Chimney Liner
Performing an annual inspection and cleaning of the chimney lining system is essential. In many cases, stainless steel liners require this for the homeowner’s safety and to meet warranty requirements.
It may be necessary to perform more frequent maintenance on solid fuel-burning appliances, depending on their use.
A complete inspection and cleaning of the entire system is required, starting at the appliance connection, and finishing at the top of the liner.
Final Words
Even small gaps or cracks in your chimney’s liner can be the beginning of a process that erodes the structure’s integrity and poses a danger to your family.
This leads to significant fire hazards, since combustible creosote or soot can also escape and accumulate outside the chimney flue liner.
The creosote will no longer be contained within the flue if a fire breaks out in this area, and so will spread outside the flue – directly adjacent to the main building structure causing serious damage.
