Disadvantages Of Ventless Gas Fireplace

In this article, we are going to discuss the disadvantages of ventless gas fireplaces.

But before we get into the details about the cons of this type of fireplace, we shall take you through some of the basic things about them. Then, we shall explain how they work and the various ways in which they differ from vented fireplaces.

More importantly, we shall discuss some of the most common advantages of ventless fireplaces. We shall then briefly discuss some of the best ventless fireplaces that you can acquire.

We hope that these details will help you make the right decision on whether to use a vented or ventless fireplace on your premises. 

What is a Ventless Gas Fireplace? 

A ventless fireplace is a gas fireplace that burns either natural gas or propane to produce heat but does not require a chimney or flue connection.

This type of fireplace is also referred to as a vent-free or unvented gas fireplace. It is designed specially to draw in oxygen from the room in which it is installed. The oxygen is used for the combustion of the fuel to produce heat energy.

The byproducts of the combustion process are then released back into the indoor space where the gas fireplace is installed. However, ventless fireplaces are engineered to draw in the required oxygen to ensure that all the fuel is burnt correctly.

Thus, these types of fireplaces do not produce poisonous gases and smoke, as one would have expected them to do. 

How do Ventless Gas Fireplaces Work?  

At the heart of the operation of a ventless fireplace is a carefully designed and manufactured regulator. The regulator is a small device that controls the amount of air that enters the ventless fireplace.

The regulator ensures that there is a fine and perfect mixture of oxygen and the fuel that is used in the fireplace. When the ratio of air to fuel is perfect, perfect or complete combustion of the fuel occurs.

When the fuel is perfectly burnt, minimal or, no fumes are produced. This is important for a ventless fireplace because this type of fireplace does not have chimneys of flues that could be used to channel the fumes to the outside. 

A ventless gas fireplace draws the oxygen that it uses to burn the fuel from the room. However, once the combustion is complete, this type of fireplace emits the byproducts of the combustion process in the same room.

Modern ventless gas fireplaces have advanced systems for monitoring the quality of the air. The most common components are carbon monoxide and oxygen detection sensors. These sensors help users determine if the fireplace is emitting any fumes into the air in the house. 

Difference Between Vented and Ventless Gas Fireplaces

There are significant differences between vented and ventless gas fireplaces. The differences are evident in the design, components, and mode of working of these two types of gas fireplaces.

Here are some of the most common differences between the two. 

  • The presence of a chimney or flue: A vented gas fireplace is connected to the outside via a chimney or flue. The chimney or flue provides a connection between the fireplace and the outside environment. There are two types of connections: the exhaust and intake tubes. A ventless gas fireplace does not have these connections to the outside environment. 
  • Mode of operation: A vented gas fireplace draws in air from the outside via the intake pipe. Once the combustion process is complete, the gas fireplace emits fumes and other byproducts through the exhaust pipe. On the other hand, a ventless gas fireplace draws oxygen from indoors. The regulator controls the amount of oxygen that the fireplace draws in. This helps to reduce the amount of fumes that the fireplace emits to the indoor environment. 
  • Heating performance: A ventless gas fireplace has a higher heating performance than a vented gas fireplace. This difference arises from the nature of vented fireplaces. Most of the heat produced by vented fireplaces escapes to the outside through the chimney or flue. Therefore, a ventless gas fireplace has a higher BTU rating than a vented gas fireplace. 
  • The risk of negative pressure: A ventless gas fireplace can easily cause negative pressure in the house. Modern houses are made to be completely airtight. As the ventless gas fireplace repeatedly draws air from the house and emits byproducts, negative pressure may develop. On the contrary, a vented gas fireplace does not create negative pressure in the house. 

What are the Pros and Cons of Ventless Gas Fireplaces?  

There is an endless debate about the merits and demerits of ventless and vented gas fireplaces. Whereas both types of fireplaces have their unique strengths, they too have some failings.

It all boils down to your preferences and the amount of money that you are willing to invest. Given that retrofit installations are expensive installing a vented gas fireplace will cost you more than a ventless one would do.

Here are some of the pros and cons of ventless fireplaces. 

vented vs ventless gas fireplaces

Advantages of Ventless Gas Fireplaces

A ventless gas fireplace can be beneficial in various ways. Here are some of the most significant pros of installing and using a ventless gas fireplace in your building. 

  • Effective heating capacity: Vented gas fireplaces and wood fireplaces have a common disadvantage: loss of heat. A considerable percentage of the heat produced by these two heating devices escapes out to the atmosphere through the chimney and flue. A ventless gas fireplace does not have a chimney or a flue. Thus, all the heat that it produces from burning the fuel is channeled to the house. 
  • Relatively cheaper to operate than an electric heater: A ventless gas fireplace can burn either natural gas or propane. The cost of propane is much lower than that of electricity. Therefore, running a ventless gas fireplace is more affordable than using an electric heater. 
  • Easy installation compared to the process for a vented gas fireplace: You need to create a chimney or flue when installing a vented gas fireplace. However, this is not the case when one needs a ventless fireplace. Thus, the cost and time involved in installing a ventless fireplace are lower than for vented gas fireplaces. 
  • They are cleaner than wood fireplaces: Wood fireplaces produce all manner of contaminants, including soot and smoke. You will have an easy time cleaning your house by installing a ventless gas fireplace because these devices do not produce soot and smoke. 
  • They are safe for placing a TV on the top: You can conveniently place your TV on the top of your ventless gas fireplace. The heat that the device produces spreads across the entire house. It is impossible to place a TV atop a wood fireplace because the device’s heat rises before it spreads around the house. 
  • More convenient to use than wood fireplaces: You do not have to worry about large backyards for storing wood pieces if you have your ventless gas fireplace. In addition, it is relatively easy to store propane and natural gas. Thus, using ventless gas fireplaces as sources of additional heat in the home is more convenient than using wood fireplaces. 
  • You can personalize your ventless gas fireplace: Ventless gas fireplaces come with a broad range of features and controls. You can use the controls to adjust almost any aspect of the performance of these devices. For example, it is possible to change the color of the flame and adjust the heating performance. This level of control that your ventless gas fireplace affords you is a huge advantage compared to what a firewood fireplace can offer you. 
  • Ventless gas fireplaces can be installed anywhere in the house: Therefore, it is possible to install your ventless fireplace in any room in your house. You do not need to think about proximity to the chimney and the creation of flues. This feature is in contrast with wood fireplaces that can be installed in specific places in the house. 

Disadvantages of Ventless Gas Fireplaces

Despite their apparent advantages compared to other types of heat sources, including wood fires and vented gas fireplaces, ventless or unvented gas fireplaces have disadvantages.

The disadvantages are associated with their mode of operation, heating effectiveness, and overall safety. 

  1. Carbon monoxide and other poisonous fumes: Although ventless gas fireplaces have regulators that ensure a perfect mixing of air and fuel, they still produce carbon monoxide and other poisonous fumes, albeit in tiny quantities. This is the reason why ventless gas fireplaces have carbon monoxide and oxygen detector sensors. 
  2. The flames are not realistic: Although manufacturers of ventless gas fireplaces like to market their products by saying that the flames are highly realistic, this is not always true. The blue flames that ventless gas fireplaces give off are far from looking like natural fires. Even the feature that allows you to change the color, speed of dancing, and size of the flames does not help matters. 
  3. The flame of a ventless gas fireplace is weak: Although the flame is designed to look as realistic as possible as it burns through the simulation charcoal or wood, the flame is weaker than a real one. Thus, there is a massive difference in the strength of the flame between a wood fireplace and a ventless gas fireplace. 
  4. High cost of installation: Retrofitting a ventless gas fireplace in your living room or any other place of choice will be costly. You will be forced to contact technicians to help you with the process. In addition, there are many technical aspects to the process. Some of them include connecting to gas lines and ventilation systems that make the procedure costly and lengthy. 
  5. The risk of a fire: The flame that burns inside your ventless gas fireplace is exposed. Therefore, you run a moderate risk of a fire outbreak every time you use your ventless gas fireplace. 
  6. The use of ventless gas fireplaces is restricted or outrightly banned in some regions: For example, you cannot install a ventless gas fireplace in any building in California State. There are stringent standards and technical requirements for installing and using ventless gas fireplaces in many other states. The requirements are supposed to guard against gases and other contaminants that occur when these devices are running. 
  7. Ventless gas fireplaces can create excess moisture: The excess moisture comes from the combustion process. If you run your ventless gas fireplace for a long time, you may realize that your home becomes a little more humid than usual. This is because the vapor that these devices produce settles into the air in your home. 

What are some Alternatives to Ventless Gas Fireplaces? 

There are many alternatives to ventless gas fireplaces. Your choice depends on whether the features you are looking for in an alternative heating source are all found in any one of the alternatives.

Here are some of the most common ones. 

Wood Fireplace

wood burning fireplace

Wood fireplaces burn authentic wood pieces to produce supplemental heat in the home. A wood fireplace can come in an open hearth, an enclosed wood insert, and a wood stove.

All these types of wood fireplaces have unique features and modes of operation. For all these types of wood fireplaces, a flue and a chimney should be available to provide a way of escape for the smoke. 

Electric Heaters

Electric heaters are the most versatile and reliable sources of supplementary heat. They convert electric power into heat energy. They have inbuilt blowers that evenly distribute the heat energy around the room.

This creates an even and uniform heating process for the comfort of everyone who may be in the room while the device is running. 

Electric heaters are easy to install and operate. One does not need to connect them to inlet and exhaust pipes because no real combustion occurs inside them. Nevertheless, you can adjust the fake flame to create effects that resemble those of a real flame. 

Ethanol Fireplaces 

Ethanol fireplaces come in different shapes and sizes. They produce heat by burning an alcohol-based fuel using an open flame. They can be placed in any position in the house because they do not need venting.

Despite using real fire, these fireplaces do not produce soot or other fumes that contaminate your indoor environment. 

Best Ventless Gas Fireplaces

Pleasant Hearth VFS2-PH30DT

The Pleasant Hearth VFS2-PH30DT is a sturdy, reliable, and highly durable ventless gas stove designed to provide supplemental heat in small to medium-sized indoor spaces.

It has a BTU rating of 30,000, which is high enough to create and maintain a comfortable indoor environment even on the chilliest days. Operating this device is a breeze.

It comes with a built-in thermostat and an overheat sensor. You can use the thermostat to determine the ideal temperature that the heater should maintain. The overheat sensor enhances the overall safety of the Pleasant Hearth VFS2-PH30DT for your peace of mind. 

Duluth Forge Vent Free Dual Fuel Ventless Gas Fireplace Insert

The Duluth Forge Vent Free Dual Fuel Ventless Gas Fireplace Insert has some beautiful features that you would expect to find in such a heating device. It is highly durable, thanks to the use of high-quality materials and exceptional artistry.

Moreover, you will find it convenient to use this heating device because it has dual-fuel technology. It can effectively run on either natural gas or liquid propane.

Finally, the aesthetic value of the flame of this fireplace is something worth mentioning. The fake logs are hand-painted to give a highly realistic feel and look. You can also conveniently adjust all aspects of the flame, including brightness and speed of burning, to your liking. 

Comfort Glow GSD2846

The Comfort Glow GSD2846 is a dual fuel gas stove that provides supplemental heat in relatively large spaces that measure about 1,300 square feet. It is easy to use at any location in your home because it does not require to be connected to inlet and exhaust vents.

Moreover, the heavy-duty black steel cabinet contrasts with the bright fake flame to create an elegant atmosphere in your home. Moreover, its 30,000 BTU rating is enough to ensure that your house is warm and comfortable.

In addition, you can conveniently alternate between LPG and natural gas. This gives you the advantage of going for the fuel that is readily available and cheaper than the other one at any given time. 


Ventless gas fireplaces are ideal for use in your home or any other premise because of various reasons. If you were keen on maintaining a clean home environment, it would be a good idea to use a ventless gas fireplace instead of a vented gas fireplace and, even worse, a wood fireplace.

Installing a ventless fireplace is much easier and quicker than putting up a vented gas fireplace. However, the flame of your vented fireplace cannot be as realistic as an open flame that is used in other devices, including a wood fireplace and an ethanol fireplace.

Moreover, even vented gas fireplaces produce small amounts of carbon monoxide and other fumes when they are running.