What are Gas Fireplace Inserts?
A gas fireplace insert is a unit that retrofits into an existing masonry fireplace or any prefabricated, factory-built fireplace that carries the correct rating. Fireplace inserts are a more affordable, painless option with relatively quick installation in comparison to completely redoing a fireplace and chimney. Additionally, fireplace gas inserts can burn either natural gas or liquid propane.
This means homes in all areas can enjoy the advantages of this type of appliance. It does not matter which fuel the masonry fireplace was designed for originally, although masonry fireplaces that originally burned coal may be too small to house an insert. But, there are a few other things you need to know about gas fireplace inserts.
What do I need to know about Gas Fireplace Inserts?
You should consider a few things before leaping into purchasing a fireplace insert. Some key areas to consider include size, BTU output, and venting options. Knowing the exact dimensions of your existing fireplace is essential for finding the correctly-sized fireplace insert.
To find the correct size for an insert, you'll need to take a few measurements of your existing fireplace. You will need several numbers, so grab a tape measure. First, you need the height and width of the opening of the fireplace. Then, you need to know how deep the fireplace opening is. Additionally, you need to know the height and width of the back wall of your fireplace. Keep in mind that some masonry fireplaces have a back wall that slopes forward, so only measure the depth at the shallowest point.
Now that you know the size of your existing fireplace, you can start to look at the sizes of inserts. Doing this will give you an idea of what sort of insert you might like to have in your home. Manufacturers of fireplace inserts will provide a detailed sizing diagram and minimum dimensions required for installation. Comparing these sizing charts against your recorded measurements will guarantee a proper fit.
Fireplaces vs Fireplace Inserts vs Fireboxes
A true fireplace insert has everything needed to replace your existing masonry construction. There has always been confusion between a fireplace, fireplace insert, and a firebox. A fireplace is any structure or appliance, masonry or factory-built, that is designed to facilitate the burning of wood or gas fuels. This term refers to the whole structure or appliance and it's important to note that these are built-in structures or appliances that cannot be easily removed. Prefabricated fireplaces have a large metal chassis the ensures the outsides stay cool, with metal spacers that allow them to be installed into wooden framing. This is not the case with a gas fireplace insert. A firebox is just the interior of the masonry or prefabricated fireplace that contains the fire. Unlike a gas fireplace insert that is fully equipped and ready to use, a firebox that is being retrofitted for gas would need a separate gas log set, a burner, and other components.
British Thermal Units (BTU)
The BTU input of a vented gas fireplace insert is important as well. This ties in with the difference between using a fireplace insert or a fireplace that has been retrofitted with a gas log set. The gas insert will have a determined BTU input based on the fuel type. With a fireplace that was previously only used to burn wood, the gas logs and burner you select will determine the BTU input.
You can easily determine the BTU input your home can accommodate. All you'll need are the measurements of the room where the insert will be installed. Next, multiply the L (length) x W (width) x H (height) x 20 to calculate the maximum BTUs your room can handle. Having this number will allow you to shop more specifically and have realistic expectations of how much area the appliance can heat. This is also a good time to determine if the appliance will truly be used for heating or is more in line with an aesthetic want.
It is up to you whether you decide to DIY the job or hire a professional. But, we recommend consulting an NFI certified technician to help with installation questions.
How to Choose Gas Fireplace Inserts
You'll want to be sure a gas fireplace insert is the right way to go for your upgrade. First, ensure you have enough space to house the new unit. Note that some prefabricated fireplaces are not rated for use with inserts. Check with your manufacturer to make sure your unit is rated for use with a gas insert fireplace replacement.
Most manufactured fireplaces will have a build plate just inside the opening with the model number listed. If you do not have the owner's manual on hand, a quick online search will often yield a result. The manual will usually explicitly state whether or not the fireplace is listed for use with an insert. It is important to use a fireplace insert only with a unit that is rated for it, otherwise overheating of the fireplace can result.
Many brands offer various stylish choices. But, most styles fit into one of two categories.
Some inserts have a classic appeal while others speak to contemporary flair. There are large ones, small ones, and some sizes in between. You can even find ones that look more like a large flat-screen TV than a fireplace.
Most inserts offer various styles of surrounds and overlays. These are the components that are used to cover the inevitable gap between the edges of the insert and the edges of the fireplace. Depending on the insert, the styles can range from a simple 3 piece steel surround to a single piece ornate cast iron overlay. Simply put, there are too many design options to list here. So, it's best to narrow down the options by your desired aesthetic. Then, you can go from there.
How do Gas Fireplace Inserts work?
The way gas fireplace inserts work depends largely on the way they are vented. They come in vented or unvented varieties and are divided into three subcategories or types. From the vented category, you can choose between direct-vent and natural vent. The choice boils down to your heating needs, budget, and available space for installation.
In this section, we'll cover these options in more detail.
Ventless Gas Fireplace Insert
Factory-built ventless inserts burn cleanly. These units are designed for a maximum of 40,000 BTUs for indoor applications. This BTU cap is to ensure that they do not consume too much oxygen from the indoor air. They are manufactured without a vent collar as they don't use venting systems. These units are highly efficient heating sources and are perfect for supplemental heating, especially for homes with large rooms and open floor plans. And, most come with a blower to circulate heat throughout your home.
As discussed earlier, gas fireplace inserts are installed into an existing fireplace. Some are secured with fasteners, but many simply rely on the weight of the insert to hold the unit in position. And, you can give them a more customized look with optional accessories. Some of the exterior accessories include trim kits, surrounds, or faux door overlays.
These options cover visible space between the opening and the outer shell of the insert. We recommend choosing an insert that is as large as possible without overpowering the room. When you balance size with BTU rating, you can have the best of both worlds.
But, be aware that some areas do not permit vent-free appliances. There are several reasons for this. The main debate centers around functionality at higher altitudes and safety concerns. They also can only be used as a supplemental heat source, since they consume oxygen from the room that must be replenished over time. For these reasons, it is a good idea to review your local codes before choosing a vent-free unit.
Direct Vent Gas Fireplace Insert
Direct-vent gas fireplace inserts are the best all-around option. With sealed openings, they offer a good balance of heating efficiency and preservation of indoor air quality. A direct vent gas fireplace insert operates with the same efficiency as a direct vent gas fireplace. They use a venting method that's similar in concept to a direct vent fireplace, but the means of how they achieve it is different.
Most direct-vent fireplace applications use coaxial vent pipes. This means that they use a pipe within a pipe - a smaller inner pipe encased by a larger outer pipe. It's a rigid system, designed to route vertically or horizontally through an exterior wall. The inner pipe is responsible for containing hot flue gases, while the outer draws outside air for combustion in the fireplace.
- Kingsman direct vent fireplace insert
Fireplace inserts instead use a co-linear design that allows you to route your venting up an existing masonry chimney. Instead of a pipe within a pipe design, it includes two separate pipes that run side by side. The pipes work in a similar fashion to a co-axial system. One pipe draws combustible air from outside. The other pipe expels unwanted combustion gases from the home through the chimney.
Many systems rely on two highly flexible liners that are three inches in diameter each. The small diameter and flexibility of these liners mean that they can easily be routed through the damper opening of masonry or prefabricated fireplace, as well as around offsets or turns within the chimney. These liners connect to a purpose-built termination that must be installed at the top of the chimney. The termination system keeps the intake air and exhaust air separate. It also prevents water intrusion. As with vent-free systems, direct-vent models are designed with efficiency in mind. They, too, feature a built-in blower system to maximize heat transfer.
Natural Vent Gas Fireplace Insert
Often referred to as B-Vent, this venting method is the closest to a wood-burning fireplace. B-Vent fireplace inserts have an open front that allows an easy view of the flames. They provide a realistic flame without the maintenance needed for a wood-burning unit.
However, B-Vent inserts have low heating efficiency. This is because they lose much of the produced heat to the chimney, much like an open wood burning fireplace. Most people install these units for aesthetic appeal as opposed to heating ability. This type of insert requires a flexible vent system that is routed through a masonry chimney, much the same as a direct vent fireplace insert. Since they use room air for combustion, they only use a single liner to vent exhaust gases. The liner is usually 3 to 4 inches in diameter.
How to Install Gas Fireplace Inserts
Installing a gas fireplace insert requires labor and good knowledge of how to perform the task. Consider the venting that will need to be run, the gas that will need to be supplied, and 120-volt power that is needed for fans and ignition systems. Fitting issues, affected by the style of the gas insert, pose the most difficulty.
Depending on access, it can be difficult to provide the necessary support systems. That's why seeking the help of a certified expert is key to your installation success.
Before installing any gas or gas stove inserts, you'll also want to consider the gas line routing logistics of your home. Of course, you can choose between natural gas or propane, but it's easiest to use whichever fuel is already supplied to your home. But, you will need a gas line. If you don't have one for your existing fireplace, you'll need to have one installed. You'll also need to determine the best point of entry for your unit.
Many prefabricated fireplaces have knockout areas. These appear within the fireplace opening or on the exterior of the fireplace jacket. Either space allows for the passing of a gas line into the fireplace. If the fireplace doesn't have a gas line in place, the installer may need to open an adjacent wall to route one.
For masonry fireplaces, it is possible to bore a hole with a masonry drill. This will allow you to route an external line into the opening of the insert. Each installation is different. So, we suggest discussing the time and cost of routing a gas line with a seasoned plumber.
You'll also want to consider any electrical components. Units that use a blower, internal lighting, or an electronic ignition system will need electricity. You can either use a nearby electrical outlet or install one.
For an existing outlet, you can route a low-profile electrical feed wire along the baseboard and into the fireplace opening. An electrical Panduit will help keep wires hidden from view. For a cleaner look, you can install an electrical outlet inside the fireplace opening. This option will need routing similar to that of a gas line.
To complete the gas fireplace insert installation of vented models, you will need flexible aluminum liners. Most manufacturers offer a purpose-built vent kit that includes these. Vent kits include universal components that meet the UL listing requirements.
Most liners for fireplace inserts will be collapsed for shipping. So, you'll need to expand them fully before installation. Also, take careful note of how the flue collar on the insert and the flue collar on the fireplace align. Unlike a masonry fireplace, there is usually no smoke chamber to accommodate venting offsets.
The ceiling of a firebox is usually flat. And, there is often less than six inches of space between the insert and the fireplace. So, it will not be possible to offset the chimney liners enough to route them into the chimney.
The owner's manual for each unit will show the measurement from the face of the fireplace insert to each flue liner. Take this information into account to make sure the vent collars and chimney opening overlap for tight installations.
The actual installation of a gas fireplace insert should be done by a licensed professional. Some manufacturers require professional installations to validate the warranty of their products.
Completing the Look
Many times, installing a fireplace insert will result in a gap between the edge of the insert and the fireplace opening. A surround can and is often required to cover this gap. A surround covers the gap between the edges of the insert and the fireplace opening.
This surround could be a multi-panel unit or a single piece. You'll need to verify that the surround is large enough to cover the fireplace opening. But, it should not be so large that it looks awkward or does not fit within the confines of a mantel or surround. Most models have several surround options.
Not all fireplace surfaces are smooth. In such cases, it can be a challenge to make a surround sit flat against uneven surfaces or ledges. You'll want to create a smooth surface for the surround or to trim.
If the surround cannot be trimmed, it is possible to overlay the surround against the face of the fireplace and trace where the surround will sit. Then, you can use castable mortar to create a thin coat over the stone to create a smooth surface.
Most fireplace inserts will arrive on a pallet via LTL freight. The freight company will call you to schedule a delivery to your home or business. But, these deliveries often require more than one person to receive the package. Upon arrival, we encourage customers to inspect their products carefully for damages. It will be up to you to refuse the package if it arrives damaged. If you accept the package and find damage later, you may not have a case for the carrier or the manufacturer being at fault.
Care and Maintenance
To keep your unit in good running condition, it's important to perform ongoing maintenance. To help, we've established a list of tips to help keep your fireplace insert operating for a long time. Among those things that should be done on a regular basis are included on the chart.
Have the insert checked out by an NFI certified technician at least once a year. Ideally, this inspection should take place around September or before the start of the cold season. Doing this will ensure that your insert is operating efficiently. It also helps prevent problems or issues or catch those that are present or in need of addressing.
How long will gas fireplace inserts last?
If well maintained, a gas fireplace insert can last between 15-20 years. To get the most years out of your appliance, follow the manufacturer guidelines. Manufacturers provide unit-specific maintenance instructions. But note that all gas fireplace inserts are vulnerable to water. So, make sure the chimney is sealed against moisture intrusion. Water exposure could cause premature corrosive damage.