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    Fireplace Insert Buying Guide

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    While the traditional masonry fireplace is great for aesthetics and adds to the "down home" atmosphere of any home, the fact is that they are not much for actual heating. If you need heat for your home and want to utilize your existing fireplace, you may be interested in a fireplace insert.

    A fireplace insert is a closed-combustion firebox that is installed into an existing fireplace to increase efficiency. You literally "insert" the unit into the old fireplace and instantly upgrade its efficiency and heating capabilities exponentially. Inserts are available for burning wood (or wood pellets) or for burning gas. Gas inserts can be direct vent, natural vent or vent-free. All of these types of inserts come standard with a blower, which is a fan that greatly aids in circulating the heat produced into the home.

    The use of the term "insert" can be confusing, as many use it interchangeably when referring to inserts and zero clearance manufactured fireplaces. These are not the same thing, as the zero clearance units can be installed into a wall or framed into a mantel cabinet, while inserts can only be installed into a pre-existing fireplace. As a result, we have two separate and distinct categories for these units here on—one for "Fireplaces" and one for "Fireplace Inserts."

    The vast majority of fireplace inserts are installed into masonry, or brick, fireplaces. While this is the predominant application, there are some manufactured (factory-built, sheet metal) fireplaces that are listed to accept an insert. However, these can be difficult to find--always refer to your owner's manual to see if your manufactured fireplace can accept an insert and how to install a gas fireplace insert. Also, some inserts themselves are not listed for use inside manufactured fireplaces, and this information will also be included in its owner's manual. If either the manufactured fireplace or the insert itself is not listed for use with the other, then an insert is only an option for installation into a masonry fireplace.

    If an insert is indeed an option for your application, we hope that this Fireplace Insert Buying Guide will be a helpful tool as you search for an insert to fit your needs. It will cover the aspects of finding the right insert: fuel type (wood, gas, or pellet), sizing and style, venting requirements, installing a fireplace insert, and more.

    Wood , Gas, or Pellet?

    The first decision you must make is whether to go for a traditional woodburning insert , a gas insert (direct vent or vent-free), or a pellet-burning insert. Most consumers who purchase inserts go the woodburning route, but gas and pellet inserts are gaining in popularity. Whichever way you go, you can count on great efficiency and vastly improved heating capability from your fireplace.

    The second decision you must make is how to install a fireplace insert. Can your original unit accept a new insert? Do the models work together via measurements and dimensions? Most manuals will have a cumulative list of which inserts will fit your unit.

    Wood Inserts

    Wood Burning Fireplace

    If you have access to plenty of wood , or you are looking for the most possible heat for your home, a woodburning insert is the way to go. Nothing can match the warmth produced by burning quality firewood, and buying the appropriate woodburning insert can not only heat things up nicely, you will surely find yourself saving money on your heating bill. Many of our inserts are more than capable of providing primary heat for many homes, so, if gathering and chopping wood is not a problem, a woodburning insert can be a very wise investment. Over time, utilizing a woodburning insert to provide heat and save on gas costs will pay for itself.

    Aside from the economic benefits of a woodburning inserts, many homeowners agree: there is nothing quite like a real wood fire. While the gas hearth industry has made huge leaps and bounds with regard to realistic appearance, the pure heat and genuine atmosphere of a true wood fire simply cannot be replicated. Oftentimes, the authentic sight, smell and sound of a woodburning insert are the ultimate selling points for many customers in the wood vs. gas debate.

    When searching for the right woodburning insert, one of the most important considerations is the size of the firebox chamber. Most of our inserts list the ideal log size on their respective item pages (usually under the "Features" section), but if you need assistance finding what size logs will fit in any insert, we will be happy to assist you. In almost every case, this information can be found within the downloadable owner's manuals, also on each insert's item page.

    Another important element of your search for the perfect insert is the style of the glass door and the viewing area. While most of our woodburning inserts have a standard arch door, some of them have decorative options available. Plus, our Napoleon models offer a webbed arch door style in a few finishes as well. Moreover, we also sell a couple of bay window models by Osburn that exponentially increase the viewing area of the fire when compared to the standard door models.

    Gas Inserts

    While many homeowners with masonry fireplaces install a gas log set, a gas insert is actually a better option if the goals are heat and efficiency. A gas insert will also come with a blower included to aid in circulating the heat, something a gas log set cannot provide. Also, while a ventless gas log set provides a good amount of heat, a direct vent gas insert is a better option for those are a bit hesitant to go with a vent-free appliance, especially in areas where vent-free units are not permitted. However, if vent-free is an option, a vent-free insert may be more appealing than a mere ventless gas log set, if you desire the heating and an added aesthetic value that an insert can provide. Of course, these vent-free inserts will come with a blower as well, so the heat will be circulated much more efficiently than a ventless gas log set.

    Gas Fireplace Insert

    If you are certain you want to go with a gas insert, the decision then comes down to whether direct vent or vent-free is right for you. The basic difference between the two is obvious; the direct vent units will require venting up the chimney, while the vent-free inserts are entirely self-contained and do not require any additional components for operation. The other main distinction is that direct vent units will have a fixed glass panel sealing the unit off from the room, while the vent-free insert will be open to the room, using room air for combustion. For more information regarding the differences between these two options, you may want to look at our Gas Fireplace/Stove Buying Guide (link), which details the pros and cons of each.

    One difference between the two that is unique to inserts is the ability to install some vent-free inserts as zero clearance fireplaces. In other words, some vent-free models, like the Empire Innsbrook or the Monessen DIS33, can be recessed into a wall as opposed to inserted into an existing fireplace. All of our direct vent models, however, must be installed into an existing fireplace and cannot be built into a wall or mantel cabinet.

    One big advantage gas inserts hold over the woodburning models is the ability to control the fire with a remote control. While all of our gas inserts come remote-ready, the remote control itself must be purchased separately. In most cases, you will have a few different remotes from which to choose. These will offer a few different functions, ranging from basic on/off control to the ability to set and operate via a thermostat. Most models also offer a wall-mount thermostat control. For some customers, this convenience is the deciding factor when choosing gas as opposed to wood.

    Pellet Inserts

    A pellet insert uses pellets of wood for fuel, fed to the fire by an automated auger. As such, these inserts will require electricity to operate, but many models have a battery back-up feature to allow operation in the event of a power outage. Pellet inserts are a bit harder to find than a traditional woodburner or a gas insert, but technological advances in the manufacturing and availability of pellets could make these inserts the best all-around choice for heat and energy efficiency over time. Pellet inserts are still relatively new to the market, so there is still a bit of a refining process ongoing.

    Pellet Burning Insert

    However, pellet inserts are a bit high maintenance, as they require constant attention to ensure optimum performance. When talking about pellet inserts the biggest maintenance concern is not with ash cleanup – as would be the case with a woodburning insert – but rather careful attention to the electronic components such as the automated loading hopper and ignition system. Any time you have many moving parts, the potential for problems increases, but our pellet inserts carry manufacturers' warranties to protect you any such complications for a certain period of time. If you go with a pellet insert, you will become rather well-acquainted with that hopper, as you may use one 40-pound bag of pellets per day. Another thing to know about these pellet inserts is, depending on the quality of pellets used, you could have some issues for those in the home with respiratory problems. The higher quality the pellet fuel, the less fine dust will be released into the air when refueling the stove.

    While pellets can be hard to find in some areas, they are readily available for purchase on the Internet. Many brick-and-mortar retailers carry pellets as well, including Home Depot, Lowe's, Tractor Supply, Northern Tool and even Wal-Mart. Please be sure to check availability in your area before making the decision to go with a pellet insert.

    Pellets overall produce plenty of heat with minimal ash content. For instance, a 40-pound bag of pellet wood produces less than a cup of ash. Pellets are available in three grades, depending on that ash content, with the higher grade pellets producing the least ash. The top-of-the-line pellets are hardwood, while on the lower end there are pine pellets. The mid-grade pellets are the most widely sold, and these are the ones you are likely to find at Home Depot or Lowe's. If you find a reliable source for pellets, particularly those of a higher quality grade, a pellet insert may be a wise investment.

    A bonus for those interested in going with a pellet insert is the ability of some models to be functioned via hand-held remote control. This is currently available on our Timberwolf TPI35 and our Napoleon NPI45 inserts.


    Measuring For An Insert

    After making the critical decision as to whether you want a woodburning, gas, or pellet insert, the primary concern will be to figure out if you have enough room for an insert in your existing fireplace. Here at, all of the information you need is available on each item page for every insert that we sell. If the appropriate fireplace dimensions are not specifically mentioned in the "Features" section, you will be able to find this information within the owner's manual, which you can download by clicking a link at the bottom of the insert's item page. If you are having any trouble finding this information, please give us a call at 1-800-203-1642 or email us at, and we will be happy to confirm whether an insert will indeed fit properly inside your fireplace.

    Since inserts are made to be able to fit inside most fireplaces, you should be able to find an insert that will fit inside your fireplace, unless it is unusually small. We do have a variety of sizes available across the wood, gas and pellet spectrum, so chances are we will be able to find one that will work for you. One of our most popular gas inserts, the Empire Innsbrook insert (available both in direct vent and vent-free) is made in three sizes – small, medium and large – to ensure compatibility with both small and large fireplaces. Our woodburning inserts range in size from the petite Napoleon 1101P insert, to the largest woodburning insert we sell, the Osburn 2400.

    Since (almost) everyone's fireplace is different, your exact opening size will determine the appropriate flashing or surround to accompany your insert. The flashing or surround will cover up the rest of your fireplace opening. Some inserts provide decorative options in this area. For example, instead of a basic black sheet metal flashing, some models provide the option to go with a cast iron surround. If aesthetics are important to you, be sure to check out all the available flashing and surround options for each model before making a decision.

    In the rare case where none of the appropriate flashings or surrounds will cover your entire fireplace openings (particularly for those with very large fireplaces), it is possible to purchase the insert only and then have a custom surround fabricated by a local machine shop or sheet metal expert. As always, we here at will be happy to assist you in finding the appropriate flashing or surround and let you know if you may need one custom made.


    In order to make your fireplace insert operate properly, you will need to vent it using flex pipe vertically up your chimney. Some consumers purchase a fireplace insert and try to install it without any venting components, and the inevitable result is the inability to keep a fire lit along with a massive headache. Fortunately, we have all the venting components you need for any fireplace insert here at

    Venting for Woodburning Inserts

    Direct Vent Fireplace

    All of our woodburning inserts have a 6" diameter flue collar on the top, so you will need 6" diameter flexible stainless steel liner running from the top of your insert to the top of your chimney. We carry a variety of different types of this flexible liner, ranging from the more budget-friendly 304-alloy stainless steel liner to the top-of-the-line 316Ti -alloy stainless steel liner. In addition to the liner itself, you will need a connector adaptor (to connect the liner to the insert), a collar plate (to cover the chimney opening and support the liner), and a cap. For many of our liners, we offer a complete insert package deal that includes the liner itself, a connector adaptor, a collar plate and a cap.

    Our stainless steel liners are available in 5-foot increments, ranging from 20 feet to 35 feet. To pick the length appropriate for your chimney, measure the distance from the top of the insert to the top of your chimney, pick the corresponding length equal to or just more than that amount, and then you can trim any excess amount of liner with tin snips.

    One very important consideration with regard to the venting will be whether or not you need insulation for the liner in your chimney. Generally, it is strongly recommended to insulate your stainless steel liner. We carry pre-cut insulation blanket kits and pour-down insulation mix for this purpose. Keeping the flue gas warm will significantly improve your draft, which, in turn, will increase the efficiency of your insert. Not only will the efficiency and performance improve, but you will also significantly decrease the potential for any back draft or smoking issues. Insulation is only required when the area of your chimney is more than twice as large as the 6" diameter liner, but it is always recommended.

    Venting for Gas Inserts

    Direct Vent Fireplace

    Venting for gas inserts obviously only applies to direct vent models, as a vent-free insert will require no venting.

    Direct vent inserts are vented with colinear flexible liners that run side-by-side up your chimney. These liners are usually 3" or 4" in diameter, one for exhaust and the other for fresh air intake for combustion. All of our direct vent inserts have vent kits that consist of liner, a collar plate and a cap. The collar plate is what will mount over your chimney top, with intakes for both liners underneath and one cap to go on top the other side. If you have a large chimney opening, you will need to mount the collar plate on top of a chase cover.

    Venting for Pellet Inserts

    Pellet inserts are vented by using 3" or 4" diameter flexible liner, such as the PelletVent Pro by Simpson DuraVent. Other options include the economical MagnaFlex or the stainless steel DuraFlex or HomeSaver UltraPro. Basically, they are vented just like woodburning inserts, with a connector adaptor, the liner and then a collar plate and cap.

    A Wise Investment

    Choosing the perfect fireplace insert can be challenging, but the result is rewarding. You will turn your old, drafty masonry fireplace into an aesthetically-pleasing, efficient heat source. Your living room will be transformed and you may find yourself saving plenty of money in the long run. If you have any more questions about fireplace inserts—about anything in this article or anything not mentioned here—please give us a call at 1-800-203-1642, or send us an email at We will be happy to assist you in determining which insert is perfect for you, as well as the appropriate accessories and vent kit for your application.

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