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A Guide to Fireplace Venting Options

Some fireplace options need to be vented outside. For instance, while electric fireplaces don’t require venting at all, gas and wood-burning fireplaces, inserts, and stoves do need to be vented to the outdoors to ensure healthy indoor air quality.

In fact, there are several different ways to route venting depending on the placement of your fireplace and the fuel it burns. So, to help you decide which venting option is best for your home and fireplace preference, consider this fireplace venting guide.

Types of Ventilation

Fireplaces are typically vented through the roof with a pipe or chimney or through the wall to the outdoors with a direct vent.

Here are different types of ventilation based on the type of fireplace or stove used:

  • Gas fireplaces are typically vented horizontally through the wall to the outdoors—direct vent—but they can also be vented vertically through the roof.
  • Wood-burning fireplaces and stoves require vertical venting through the roof.
  • Pellet stoves are often vented horizontally directly through the wall to the outdoors.
  • Fireplace inserts are typically vented horizontally through the roof using an existing chimney.


With a direct vent fireplace, the venting is routed directly through a wall to the outside, either with rigid or flexible vents. Direct vent fireplaces have two chambers. One draws fresh outdoor air into the sealed firebox for combustion, while another expels the fire’s combustion exhaust, gases, and by-products outside.

Cool indoor air is drawn into the lower chamber, circulates around the firebox, and is released as warm air into the room with a fan. The central burner also emits radiant heat from the face of the unit, adding more heat to your living space.

The vent terminal is mounted outside and connects to the fireplace indoors. The venting exits either from the top or the back of the fireplace, providing flexibility for installation. And there is also a rear exhaust vent.

Direct-vent power venting can go up, down, and around most objects in a space, such as around stairways. So, there are versatile installation options allowing for more flexibility with your chosen fireplace location.

Compared to chimneys, this type of venting eliminates drafts and cold spots, maintains indoor air quality, improves efficiency, and distributes heat evenly throughout the room.

Direct-vent fireplaces can also operate without electricity, using batteries or a self-generating system to power the blower and other accessories. This feature is especially important if there is a blackout in the middle of winter.

Direct-vent systems are either:

Top Vent

With a top vent fireplace, aka co-linear direct vent, the venting is routed vertically through an existing wood-burning chimney.

Side Vent

A side vent fireplace, aka co-axial direct vent, is vented horizontally through a wall to the outside. Zero-clearance direct vent fireplaces are used in homes without existing fireplaces and chimneys.

Natural Vent (or B-Vent)

A natural vent gas fireplace, also known as a B-vent fireplace, draws in combustion air from inside the home and vents the combustion by-products through the roof via a pipe venting system or a brick and mortar chimney. Natural vent systems are considered the least efficient venting option since heated indoor air is lost to the outdoors, and cold air can enter the home through the chimney.

Power Vent

Power vent systems use a fan-powered accessory along the vent to increase air exchange and allow for longer vent systems. Due to the long vent run, a power vent fireplace can be installed in areas where other vent systems and fireplaces may not work, such as a freestanding wall.


Vent-Free Fireplace

Vent-free fireplaces do not have venting to the outdoors via a chimney, pipe, or direct vent. These fireplaces can be installed almost anywhere in the home. And none of the heat generated is lost to the outdoors. But since these fireplaces don’t have venting, the pollutants from combustion end up in the indoor air.

Vent-Free Gel Fireplace

These fireplaces burn a gel substance that usually comes in a can to produce flames. And the gel can even imitate the smell and sounds of a wood fire.

Gel fireplaces come in a variety of designs and styles, including hanging gel fireplaces. They are also used in outdoor living spaces.

Vent-Free Electric Fireplace

Since there is no combustion in an electric fireplace, these fireplaces are always vent-free and are perhaps the safest vent-free option.

They rely on electricity and LED lights to produce artificial flames. And they also act as a space heater, with the heat being optional.

They are mobile, compact, and can be easily used in most areas of the home, often with a remote control to adjust the temperature and flames.

Natural Gas vs Propane

If you opt for a gas fireplace, the fuel you use will depend on several factors, including access to fuel.

Natural Gas

Natural gas is more readily available in urban and suburban locations. And you may already have a natural gas hookup to your home.

Since natural gas is directly piped into your home, it’s a more convenient fuel option than propane, which requires tanks to be filled. It’s also more affordable than propane.


If you live in a rural area, you may not have access to a natural gas utility line. So, propane may be your only option for fuelling a gas fireplace.

No matter how well vented your fireplace is, always keep safety in mind. Whether you have a direct-vent gas fireplace or wood-burning fireplace stove or insert, make sure you install a carbon monoxide detector in your home.

Carbon monoxide (CO) is an odourless, invisible, and toxic gas by-product of burning wood, kerosene, natural gas, and propane. And if CO levels get too high in the home, this gas can cause CO poisoning. But with a CO detector in working condition, you will be alerted of any risk.

For more information on the best type of fireplace and venting options for your home, visit your local fireplace experts. With so many options to choose from – and bit of help from the experts – you can find the perfect spot in your home for your new fireplace.