Install a Gas Fireplace Insert

A gas insert can transform a drafty old fireplace into an energy-efficient — and beautiful — supplemental heating source.

When my wife and I designed our home in 1992, a fireplace was one of the luxuries we wanted most. As a less expensive alternative to a traditional masonry fireplace, we had an all-metal prefabricated wood-burning unit installed within a chase. And for a while we enjoyed the warmth of fires fueled by wood cut from our own lot.

Fast-forward 20 years. Those cozy fires were a rarity — and a production. Besides cutting, splitting and transporting wood, we had to round up fire starters, kindling and tools and then prop open an outside door to prevent billows of smoke from wafting through the family room. The dirt, mud and ash from the wood accumulated in our carpets, and the fireplace was so inefficient that our furnace had to work harder to heat the house. Using the fireplace became more trouble than it was worth. That’s when we started considering a gas conversion.

Advantages of Gas
Gas fi replaces have several advantages over wood-burning models. They are clean, efficient and safe. According to the U.S. Department of Energy (DOE), an inefficient wood-burning fireplace can exhaust as much as 24,000 cu. ft. of air per hour to the outside, which in turn draws cold air in through the home’s doors and windows. The DOE considers older wood-burning fireplaces one of the most inefficient heat sources a homeowner can use.

Wood fires also produce pollutants, making air quality a valid concern. The American Lung Association recommends that consumers avoid wood fires, referring to research that names woodstoves and fireplaces as major contributors to particulate-matter air pollution in much of the United States.


New developments in gas-insert design include larger viewing areas, high-definition logs and antiglare glass.

Understanding Your Options
When considering a gas conversion, you have several options. The first (and least expensive) is to buy gas logs for your existing fireplace. Two types of gas logs are available: vented and vent-free. Vented gas logs require that the damper be permanently open to allow exhaust to escape up the chimney, causing potential heat loss when the logs are not burning. You can install glass doors to help prevent heat loss, but that will drive up the price. Vent-free (or ventless) gas logs don’t require opening the damper, but they should be used only for short periods of time because the traces of exhaust they produce may contain carbon monoxide and moisture. In fact, vent-free logs are not legal in all areas.

Another approach is to install a gas fireplace or insert, available in three main styles: B-vent, vent-free and direct-vent. A B-vent gas fireplace uses air from inside the home for combustion and vents it up a chimney. This type of fireplace works much like a home’s furnace. Some models include a blower to help move heated air into the home.

Vent-free gas fireplaces do not vent the exhaust outside; they use a high-temperature “superburn” to eliminate fumes. This type of gas fireplace is not recommended for people who have breathing problems or heart conditions. And like vent-free gas logs, vent-free gas fireplaces and inserts may not be legal in certain areas.

Direct-vent gas fi replaces or inserts are efficient because they feature sealed combustion systems, meaning that they use outside air for combustion and vent the exhaust outside the home. Matt Hareldson, brand manager for Heat & Glo, explains, “One-hundred percent of the air necessary to produce a flame comes from outside the home through a direct-vent pipe, eliminating the heat loss associated with conventional chimneys. That pipe also expels 100 percent of the fire’s combustion exhaust outside the home, protecting indoor air quality.”

When shopping for a gas fireplace, choose the most efficient model that fits your space, lifestyle and budget. Most manufacturers produce higher-and lower-end models. Heating ratings can range from less than 8,000 to 150,000 Btu. In most cases, several door styles and interior brick choices are available. LED lighting, remote controls and thermostats are popular amenities. Recent innovations include realistic masonry, high-definition logs detailed to look more like actual wood and antireflective glass.

Installing an Insert
The installation of a gas fireplace or an insert should be left to professionals. In a matter of a few of hours they can turn a heat-wasting wood-burning fireplace into an efficient, beautiful gas model. For a direct-vent insert installation like the one shown here by Heat & Glo, a trip to the roof is usually required to access the top of the chimney flue. Also, a gas line and electricity should be in place before the installation begins.

In a typical insert installation, the old fireplace doors and any exterior surround must be removed. Some cutting may be required for the insert to fit into the existing fireplace (photo 1). The flue liner and/or damper are removed, and two flexible metal pipes are fed down the chimney to the firebox, one for fresh air and the other to vent exhaust (photo 2). Next, the firebox is set into the opening to ensure that it fits and then carefully prepared for the gas and electrical connections (photo 3).


Cutting away parts of the existing fireplace may be necessary to accommodate a new gas insert.


Two flexible pipes run up the existing chimney to provide fresh air and allow exhaust to escape.


The insert is set into the fireplace to check its fit and then hooked up to the electrical, gas and venting lines.

Once it has been dry-fitted, the firebox is carefully secured in the existing fireplace. The vents are attached and a surround is installed on the face of the insert (photo 4).


A surround is attached to the insert to cover the open areas around it. The surround also supports a door.

The aesthetic components of the insert are installed last. Ceramic logs are placed precisely according to the manufacturer’s instructions, and to achieve the illusion of a glowing bed of embers, glass rock and special ember material are placed along the bottom and around the burners (photo 5). These additions give the fire a more natural appearance. The final step is the installation of a fixed glass assembly and a decorative outer door (photos 6a and 6b), which may include a wire-mesh screen to prevent accidental contact with the glass.


Ember material, glass rock and ceramic logs are carefully placed around the burners.


After the logs are in place, a tempered-glass panel is set into the opening to seal the firebox.

Our technician provided a primer on the remote-control system in our fireplace. It was surprising how many options are available on new models, from flame and fan control to thermostat and timer operations (photo 7).


The Heat & Glo Escape Series gas insert shown includes a remote control with a built-in thermostat, timer and flame control.

Since we added the gas insert, my wife and I have used the fireplace more, and our furnace runs less. Besides saving money, the new system is clean, convenient and trouble-free. Gone are the days of messy fires that wasted more heat than they produced — not to mention the drudgery of cutting, splitting and hauling wood. Our dreams of hearthside luxury have finally come true.


Michael R. Anderson is a freelance writer, photographer and illustrator from Minneapolis, Minnesota. Technical assistance was provided by Heat & Glo, a member of Hearth & Home Technologies Inc.