How To Install a Gas Fireplace Insert (Video)

A gas fireplace insert can transform your existing fireplace into a convenient heat source. This upgrade saves you time collecting wood or cleaning ashes while improving energy efficiency in your home. This Old House experts, Richard Trethewey and John Sullivan, demonstrate the installation process in the video above, highlighting key steps and professional insights. In this guide, we’ll walk you through installing a gas fireplace insert. 

Understanding Gas Fireplace Inserts

Gas fireplace inserts are designed to fit into existing fireplaces, providing a more efficient heating solution. They draw air from outside for combustion and vent exhaust gases back outdoors, eliminating drafts and heat loss associated with traditional fireplaces.

Gas fireplace inserts have some advantages over wood-burning fireplaces. They’re more convenient with an instant on/off remote control, providing better heat output and lower energy costs. You don’t have to worry about cleaning up ash or soot, and you eliminate the risk of sparks or chimney fires. You also have many different styles and sizes to choose from to fit your existing space.

Preparing for Installing a Gas Fireplace Insert

Before beginning the installation process, there are a few necessary steps for a smooth and safe project.

Safety Precautions

Working with gas and electrical lines requires caution and expertise. It’s highly recommended that you hire a professional for this installation. However, if you choose to proceed independently, check that you have the necessary permits and can follow all local building codes.

Tools and Materials Needed

Gather the following tools and materials before starting:

• Caulk gun
• Chimney liner kit
• Drill/driver
• Electrical wiring and receptacle
• Flexible gas supply line
• Gas fireplace insert
• High-temperature silicone sealant
• Pliers and wrenches
• Termination fitting and weatherproof cap
• Voltage tester

Gas Fireplace Insert Installation Process

Installing a gas fireplace insert involves many steps, from preparing the chimney to making final connections. If you’re working up on your roof, take extra precaution by using either safety gear or an aerial work platform.

Chimney Preparation

To start, you’ll need to prepare your chimney:

1. Remove the existing chimney cap and damper to make room for the new liner installation.
2. Clean the chimney thoroughly to remove any debris or creosote buildup.
3. Check for any damage or deterioration in your chimney that may need repair before you continue.

Installing Chimney Liners

With your chimney ready, it’s time to install the liners:

1. Drop both the airflow intake and exhaust liners, guiding them down the chimney flue.
2. Secure the top plate using a high-temperature silicone sealant to fix it to the chimney top.
3. Attach a termination fitting, connecting it to the ends of the liners.
4. Install a weatherproof cap to protect your chimney and fireplace against outdoor elements.

Gas Line Installation

Running a new gas line is an important part of the installation process:

1. Tap into the existing gas supply and install a T-fitting and shut-off valve.
2. Run pre-cut lengths of gas piping, securely threading them together.
3. Using pipe dope, apply it on all the joint connections to prevent leaks.
4. Extend the gas line to the fireplace location (typically runs through the old ash pit).

Electrical Connections

Electrical setup is required for the fireplace insert’s operation:

1. Safely run electrical power to the fireplace location.
2. Install a duplex receptacle, placing it in a convenient spot near the insert.
3. Check that all wiring meets local electrical codes and is properly grounded.

Inserting the Fireplace Unit

With the preparatory work complete, it’s time to install the actual fireplace insert:

1. Slide the insert into place, carefully aligning it with the chimney opening.
2. Connect the flexible gas supply line and attach it to the insert’s gas inlet.
3. Plug in the insert’s power cord using the newly installed receptacle.
4. Secure the final gas connection between the flexible supply line and the insert.

Finalizing Connections and Testing

Check that everything is properly connected and functioning:

1. Turn on the gas supply and test for leaks with a soap solution.
2. Connect the liners to the top of the insert using a high-temperature silicone sealant.
3. Install glass doors or the front panel on your fireplace insert.
4. Test the insert using the remote control, checking for proper ignition and operation.

Gas Fireplace Insert Maintenance and Safety

Regular maintenance is necessary for safe and efficient operation of your gas fireplace insert.

Annual Inspections

Schedule annual inspections with a qualified technician to check for gas leaks, clean the burner and control compartments, inspect the venting system, and verify the proper operation of all safety features.

Safety Tips

To safely operate your gas fireplace insert, keep the surroundings free of combustible materials, and don’t leave the fireplace unattended while it’s on. You should also install carbon monoxide detectors to monitor gas levels if they’re not already in your home. 

Gas Fireplace Insert Energy Efficiency Considerations

Gas fireplace inserts can improve your home’s energy efficiency. They provide targeted heat where you need it, allowing you to lower your overall home heating costs. Some models offer efficiency ratings of up to 80%, making them a good choice for many homeowners.

To get the most out of your gas fireplace insert, you can use the thermostat feature and close unused rooms for better heat concentration. You can install a ceiling fan to distribute warm air more effectively and use the fireplace insert along with your primary heating system. Gas fireplace inserts also reduce the reliance on wood, contributing to lower emissions and a smaller carbon footprint.

Our Conclusion

Installing a gas fireplace insert is a worthwhile investment. While the process involves several steps, the result is a convenient, clean-burning heat source. For most homeowners, professional installation is the safest and most reliable option for proper function and longevity.