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How To Understand Confusing Fireplace Terms

How To Understand Confusing Fireplace Terms

For anyone who owns or is installing their very first fireplace, understanding hearth terminology can be challenging. Many terms are very similar and sometimes used interchangeably. While others may appear similar but are actually quite different.

How To Understand Confusing Fireplace Terms
Napoleon High Country Wood Burning Fireplace

In this article, we will discuss many of the commonly used terms for fireplaces, fire pits and all types of heaters. We hope this will shed some light on the terms that are most confusing and give you new understanding of installing and maintaining your fireplace.

General Fireplace Terms

A fireplace is a heating appliance either built of stone or brick into the wall of your home or a complete appliance manufactured in a factory that is installed as a whole unit. A fireplace includes the firebox and the related fuel components, whether it be gas, wood, ethanol or gel fuel.

How To Understand Confusing Fireplace Terms
Breckenridge Vent Free Firebox

What can be confusing is understanding the difference between a fireplace and a firebox. A firebox is the inner box of a fireplace or stove that houses wood, faux logs and/or decorative media. The firebox is simply the interior box and does not indicate the fuel type or appliance type.

While some people use the term "stove" to refer to a cast iron, wood burning stove, modern technology has created a new breed of stoves that can burn many types of fuel. These days a stove can be made from cast iron, steel, or soapstone and burn wood, gas, pellets or operate on electricity.

How To Understand Confusing Fireplace Terms
fireplace insert

Last but not least in the soup of indoor heater terms is the fireplace insert.A fireplace insert is a unit designed to fit inside an existing fireplace. Inserts are usually designed for existing masonry fireplaces, although some manufactured fireplaces accept inserts. Fireplace inserts typically are for people who want to change the fuel of their current fireplace. While you can upgrade from a wood burning fireplace to a gas one, you can not convert gas to wood. The piping that is run for gas fireplaces is not rated for the heat and particulate of a wood fire.

Fireplace Venting Terms

Now that we have a good handle on confusing terms related to the fireplace itself, lets move on to terms related to venting.

A chimney is the full assembly that includes the venting system and chimney termination where exhaust gases escape through.

How To Understand Confusing Fireplace Terms
stove adaptor

Before we get to the actual vent pipe we need to discuss the stove adaptor. Stove adaptors are special tapered sections of pipe that help vent pipe connect to fireplaces and stoves. They create a secure connection between the stove and the pipe to ensure air flows smoothly and nothing escapes the piping before it exits the building.

The vent and flue are terms that are used synonymously for the inner metal venting of the chimney that connects to the firebox. This piping is where the exhaust gases flow through to exit the home. Within that venting system, you may find something called an offset.

Offsets are an angled piece of pipe, also called an "elbow", that changes direction and angle of the vent pipe. If you need to run your piping through attic space that doesn't allow for a straight vertical shot to the roof or if you have to turn it horizontal, you will need an elbow or offset to change the direction of your piping system.

Similar to offsets are tees. Tees are pretty easily described as they are literally a "T" shaped piece of pipe that connects various venting systems. They are used to convert horizontal stove pipe or pellet venting to a vertical direction.

How To Understand Confusing Fireplace Terms
tee vent pipe

Another term you may hear pretty often is damper. Dampers are flaps that open and close inside the flue of your fireplace. ( Since we just talked about flues, you now know exactly what that is. :) ) When the damper is closed, it seals off the chimney so the warm air from your house doesn't escape.

When the damper is open, and flue gases escape, they will rise up through the flue and exit through the chimney cap or termination. Chimney caps are round, square or uniquely shaped pieces of material that allow gases to leave a chimney system while protecting the chimney from outside elements. Debris, rain and animals can sneak into your chimney if it is not covered. So, adding a chimney cap, or termination, will protect your chimney from being filled with anything that may block it from operating effectively.

How To Understand Confusing Fireplace Terms
surface mount chimney cap

The storm collar creates a weather-resistant seal between the vent pipe and the flashing. It helps deflect rain away from the surface of your vent pipe so nothing seeps in through the cracks. The storm collar is used in conjunction with sealant against the leading edge.

Fireplace Type Terms

Having a good understanding of how fireplace venting works is essential for operating your appliance. If you are a DIYer and want to learn how to install a fireplace, this section will help you decide which venting system will best suit your needs.

Masonry fireplaces and their vents are typically made from brick, stone or clay. This type of fireplace is built into the structure of the home. This is the most traditional look that many gas fireplaces try to mimic though, wood is the fuel of choice for most masonry fireplaces.

How To Understand Confusing Fireplace Terms
Masonry Fireplace

If you are interested in a gas fireplace, a direct vent fireplace is a good place to start. They contain a firebox closed in by a glass door. The venting system is unique because it is a pipe within a pipe system. One pipe exhausts fumes to the outside while the other pipe brings in fresh air from the outside for combustion. The closed firebox setup and coaxial pipe system leads to this being the most efficient type of vented gas fireplace.

The next option for gas fireplaces is the B-vent system. B-vents typically burn natural gas or propane. This system has an open firebox that draws cool air for combustion out of the living space. With a vertical venting system, it exhausts fumes straight up and out of the home.

This setup isn't nearly as efficient as the direct vent system though, it looks more like the traditional masonry fireplace. So, deciding whether aesthetics or efficiency is your top priority will help you decide which one is right for you.

How To Understand Confusing Fireplace Terms
Vent Free Ethanol Fireplace

Last but not least we have vent free fireplaces. Vent free fireplaces are fueled by gas, ethanol or electricity. The unique thing about this fireplace is that it has no venting system. It is open to the living space it is housed in and made to burn extremely clean so it releases limited fumes into the home.

Some people question the safety of ventless fireplaces, though many tests have been run to make sure these appliances meet standards acceptable for pregnant women, the elderly and children. When installed per manufacturer instructions, there is no need to worry when it comes to vent free fireplaces.

Heating And Ignition Terms

Understanding venting systems is important for anyone who already owns or is looking to buy a fireplace. Equally important is having an understanding of ignition systems. The pieces that come together to create the heat in your fireplace along with the pieces that vent exhaust fumes are some of the most important components for any heating appliance.

When discussing heat, one of the most important terms for you to understand is the BTU. BTU stands for British thermal units. BTU's measure the level of heat that a fireplace, stove or heater is capable of putting off. So, before you buy a fireplace, figure out how many BTU's it puts off and use this BTU calculator to figure out how much heat is right for your home.

How To Understand Confusing Fireplace Terms

The most basic component of any gas heating system is the burner. A burner is a piece of metal that gas fuel runs through to spark a flame and ignite the fireplace. Burners can come in many shapes and sizes, depending upon the shape of your fireplace or fire pit which we will discuss later in this article.

When discussing ignition systems one of the most common is the Millivolt or standing pilot system. This type of pilot light involves a system that burns even when in standby mode. The pilot light does not switch on and off with the click of a button. It requires three different steps to turn on. Once it is turned on, it will continue to burn until you shut it off.

The IPI, or intermittent system, allows for the pilot light to only be lit when needed. To use this system, you can use the switch on the appliance, a wall switch, or remote to activate the ignition system. The control module will send voltage to the ignitor to automatically light the pilot. Once the pilot lights and is stable, the burner will also light.

Variable Flame doesn't refer to an ignition system so much as the ability of a system to adjust the flame height and intensity. With a variable flame option, the flame of a fireplace can be controlled by a remote and also set to change colors.

How To Understand Confusing Fireplace Terms
Variable Flame Remote

Combustion air is a term that applies to wood and gas fireplaces alike. Combustion air is cool air supplied to a stove, fireplace or fire pit. It can be supplied through a venting system that takes it from the outdoors or an open firebox that sucks it from the inside. This cool air aids in the combustion of fuels, so heat is created and a fire sustained.

Lastly, we can discussinfrared heat. This really has nothing to do with ignition systems, but it is a form of heat so, we are going to talk about it. Infrared heat works a lot like the sun because it heats by radiation. Radiation is the act of transferring heat from one object to another without touching it. Electromagnetic energy moves from the warm object to the cool one and quickly warms stationary objects versus waiting for heat to fill a room.

Fireplace Style Terms

After learning about types of venting and ignitions, you might think there is no way to have more customization options. Well, if that was your thought, I am not so sorry to say you are wrong. For this section, we are going to discuss fireplace styles and how to choose the best shape for your space.

How To Understand Confusing Fireplace Terms
Linear Fireplace

First, there is the Linear fireplace. This is sometimes called a ribbon or contemporary fireplace, because of its lean, long shape that leans towards modern design and is a bit different from the traditional square look. Linear fireplaces can be fueled by electricity or gas, but not wood. The vertical firebox is not high enough to stack real wood logs for burning. They have a long, shallow burner tube that spans the length of the firebox and creates a row of flames. The units are typically mounted at eye level for the greatest impact.

Next is the corner fireplace. The corner fireplace is a two-sided fireplace, shaped like a rectangle, that fits into a 90-degree corner of a wall. These models have two-sided glass faces that both expose the firebox. Some people get a corner fireplace and an angled corner fireplace confused because of the name. Though, their shape is quite a bit different.

Angled corner fireplaces have triangular enclosures that are framed into the corner of a room so the front of the fireplace is at a 45-degree angle to the adjacent walls. From the outside, an angled corner fireplace looks exactly like a traditional fireplace with a single, square opening.

How To Understand Confusing Fireplace Terms
Fireplace style diagram

Unlike the traditional fireplace that only has one viewing angle, See-Through Fireplaces have more can have many viewing angles. See-through fireplaces can also be referred to as double-sided or peninsula fireplaces. The design allows you to enjoy the fire from many different sides and gives you a wider range of design options for your space. Available in both indoor and outdoor models, you can even install a multi-sided fireplace as the focal point of more than one room.

The sister to the see-thru fireplace, the Peninsula Fireplace, has three viewing sides ( front, back, and one on the side) compared to the see-thru that may only have two available. They can be used in both indoor and outdoor setups and made to burn wood though gas is more common.

How To Understand Confusing Fireplace Terms
Island Fireplace

The Island Fireplace is like a combination of the peninsula and the see-thru fireplace, as it has all four sides open. Their name comes from the installation site commonly being in the middle of a room creating an "island". Having four see thru walls allows the viewer to see the fireplace from all angles & enjoy it no matter where they are seated.

Terms Related To The Outside Of A Fireplace

Now that we have discussed fireplace styles and their venting systems, we can move onto the sometimes decorative but often necessary pieces that create the outside "face" of the fireplace.

Blowers can sit on top of your fireplace or stove or they can be attached to the inner portion of the appliance. Blowers have circulating fans that move hot air away from the heater so it redistributes further into the room. Blowers are a cost-effective way to achieve even temperatures throughout your space & get the most out of your fireplace or stove.

Louvers are a totally different category of accessories for your fireplace. They make up a portion of a fireplace faceplate that sits on the outside of the firebox and is used for decorative purposes. Louvers can be removable and typically sit along the top and bottom of the firebox.

How To Understand Confusing Fireplace Terms
Fireplace Surround

Surrounds can be confused with louvers because they are found in the same area and are both made from metal. Though a surround is a metal frame that covers the opening around the fireplace between an insert and the original walls. Surrounds are often an extra safety barrier and can help with drafting issues. They create a tighter area for combustion and limit the heat that escapes up the flue.

Lastly, there is the mantel. Mantels sit above the fireplace on the outside and can be made from wood or stone. Mantels are used for decoration, storage or a shield from intense temperatures for delicate hanging objects, like TV's. Though we do not recommend hanging a TV above a fireplace.

Fireplace Accessory Terms

We have spent a lot of time reviewing terminology related to fireplace shapes, venting and customization. Though, we couldn't complete this article without touching on a few words related to fireplace accessories. There are many more fireplace accessories than what we will discuss here, though these terms are the ones that tend to cause the most confusion. So, let's get started.

Firebacks are solid metal plates that sit along the back wall of your fireplace. They protect the masonry ( brick, stone or otherwise) and reflect heat back into your home to increase energy efficiency.

How To Understand Confusing Fireplace Terms
Pennsylvania spring fireback

They could easily be confused with a fireplace screen because of their shape and location relative to the fireplace. Though screens are standing or sliding materials, located on the front of the fireplace, that protect the surroundings from embers or ashes that may fly out during operation.

Another similar but different term is the Barrier screen. Barrier screens are made specific to the direct vent fireplace that we discussed earlier. They are designed to cover the glass front and prevent burns. They consist of a rigid perimeter frame and a single panel of tensioned mesh, designed to be tight enough that the screen cannot be easily pressed inward to contact the glass.

How To Understand Confusing Fireplace Terms
Stove board

Another accessory that is made for fireplace safety is stove boards and /or stove pads. Stove boards protect floors and walls from embers that may fly out of your heating appliance They provide a barrier between blazing temperatures and combustible surfaces. You can use them underneath a wood-burning stove to protect the floor or you can lay them in front of your fireplace to protect the hearth.

Fireplace liners or panels are less about safety and more about increasing the beauty of your heating appliance. Liners are made from a variety of materials that line the walls of your firebox and add an extra layer of decoration. You may also hear words like ceramic refractory or ceramic fiber when referring to fireplace liners (or gas logs).

Ceramic refractory materials are similar to reinforced concrete and can be used to create fireplace panels. Ceramic refractory panels are resistant to damage from high heat & very durable. Unlike the strength of the ceramic refractory panels, ceramic fiber panels are light and made from material similar to cardboard. These will not be the longest-lasting option for panels or gas logs, though, some people prefer low price over durability.

How To Understand Confusing Fireplace Terms

Moving onto the next item in the accessory category, we have andirons. Andirons are decorative fireplace tools that usually come in pairs and function as a support and brace for fireplace logs. They have a long history of usefulness in the hearth industry and recently have exploded with options in color, style and size. You can find an andiron to match just about any decor these days. There are even some shaped like cats.

If you love the look of a wood fireplace but enjoy the low maintenance of gas, you might want to consider investing in embers. Embers are glowing coals that mimic the real embers of a wood fire as the logs fall apart. You can insert faux embers, made from ceramic fiber or volcanic rock, into a gas fireplace to add ambiance and increase heat production.

How To Understand Confusing Fireplace Terms
Fire Glass

Another good accessory for gas fireplaces is glass media and/or fire glass. Fire glass is made up of small bits of tempered and colored glass. They go into your fireplace or fire pit and add a bit of decorative flair underneath the flames.

Now we have reached the end of this article. Whew! We made it. We've discussed a ton of terms today. Your brain may be on fireplace overload and that's OK. This article will always be on our website for you to come back to and reference when you need. Should you have any other questions, call our NFI-certified techs at 800.203.1642.

About the Author

Collin Champagne

With over 13 years in the industry, Collin is a National Fireplace Institute (NFI) certified technician and managed content for the eFireplacestore and eCanopy brands. He has achieved the highest NFI certification possible as a Master Hearth Professional and is certified in all three hearth appliance fields: wood, gas, and pellet. With experience with sales and in-field installations, his expertise shines through his technical knowledge and way with words.

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Customer Q&A with Product Specialists

Stuart M. from hudson ohio asked:
How is fireplace size measured?
How is fireplace size measured?
Typically, most models of fireplaces are listed by width (left to right), but this is not always the case. It is best to look at the specs for the exact model you are interested in to see a full breakdown of width, height, and depth, as well as clearances around the unit.
Answered by: Cody S. on Oct 23, 2023


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