Ventless Gas Fireplace Buying Guide


If you don’t want to worry about the hassle of cutting down trees, splitting wood, only to wait two years for it to be fully seasoned enough to use it, then you might want to take a look at ventless gas fireplaces. 

Ventless gas fireplaces are becoming popular because they’re clean and easy to use. And as the name suggests it doesn’t require you to have a chimney or exhaust system

In today’s post, we’re going to help you get an idea of how to buy one.


Table of Contents


Quick Overview


Are Ventless Gas Fireplaces Safe


What types of Ventless Gas Fireplaces are Available?


Ventless Gas Fireplace vs Other Fireplaces


How to Choose the Right Fireplace


Cost of Ventless Gas Fireplaces


Final Tips Before Buying


Quick Tips for Hiring a Chimney Company

Quick Overview

Ventless fireplaces are relatively new to the market. At least compared to the other types of gas appliances, but the appeal really comes from its name.

With no venting, you don’t have to worry about designing a chimney system or buying any venting pipe.

They’re also incredibly efficient since the lack of a vent means no heat can escape through the chimney.

chimney caps & no caps

What are Ventless Gas Fireplaces

Ventless fireplaces are a type of residential gas heating device.

They are preferred by a lot of customers because they burn at nearly 100% efficiency, release far less harmful gasses than other portable heating alternatives, and the installation is relatively simple.

Most people today don’t use their fireplace as a primary source of heat, and even though ventless gas fireplaces are still capable of heating a small house, they can still be the main heat source.

Ventless fireplaces are powered by natural gas or propane. Because they don’t require a flue, they’re perfect for newer apartments and homes without thermal vents.

They’re also less expensive and easier to install than any traditional fireplace.

How Do Ventless Gas Fireplaces Work?

Ventless fireplaces work by connecting a gas unit to a gas line – either propane or natural gas.

A professional plumbing or gas contractor must complete the installation to ensure the heating capacity doesn’t exceed the manufacturer’s requirements.

These fireplaces can be installed anywhere that’s accessible by a supply line. Many newer models come equipped with automatic ignition that will eliminate the need for standing pilot to save energy.

They also operate on battery backup mode in the event of a power outage.

Ventless fireplaces use interior air for combustion, which includes anything present in the air and on the burner. And then release all the emissions inside the room they operate.

Which actually decreases the air quality you breathe.

Ventless fireplaces release the emissions of their burn, including noxious gases such as nitrous dioxide and carbon monoxide into your home instead of outside through a flue.

Are Ventless Gas Fireplaces Safe?

At this point, you’re probably wondering if it’s even safe to have a vent free fireplace in your home. The answer is: “It depends.”

There are plenty of things you need to be aware of. Such as common complaints and air quality.


Common Complaints

We’ve seen a spike in popularity in ventless appliances in the last couple years. And people in the industry longer than us tell us that it’s been that way for about 20 years now. 

With more users come more complaints. Some complained of soot, while others complained of condensation and mold. 

Some complained about bad smells.

People began to have serious concerns about their breathing. And it’s no wonder when you find reports of burning eyes, itchy throats, and sinus problems. 

We’ve even seen reports of headaches, lethargy, dizziness, and disorientation. 

Most of the complaints about vent-free hearth appliances come down to concerns about indoor air quality and property damage. 

You should be concerned about both. 

Air Quality

Indoor air quality is all about what makes it into our bodies through our lungs. 99% of what we breath in is oxygen (21%) and nitrogen (78%). The rest is a combination of other gases and particles. 

Luckily, most are harmless. 

But there are many that can cause a lot of problems. These are particles and Gases. 


Solids and most liquids that float around the air are collectively just called particles. Some occur naturally. Others are from manufacturing or fabrication processes.

Some are released when things are burned incompletely.

Wherever they come from, particles are concerning because they can become lodged in our lungs.

Our lungs have natural defense mechanisms in place to guard against normal amounts of particles.

But when the mechanisms are overwhelmed, the results can range from irritation to damage.

Some kinds of particles, such as creosote, are even known to be carcinogenic, which means that these particles contribute to the formation of cancer.


You know what a gas is. 

Gases are free molecules that remain separate from each other without condensing into a liquid or solid. 

Just like with particles, gases become part of the air that we breathe. But while some gases are irritants, others actually make it into our bloodstream and affect how our bodies function. 

Here are a few that occur with the vent-free appliances: 

  • Nitric Oxides
  • Carbon Monoxide
  • Carbon Dioxide
  • Oxygen
  • Water Vapor


Our bodies can deal with trace amounts of impurities.

But there’s a level that we can’t deal with in a healthy manner.

Even if pollutants always exist, we’re lucky that ventilation keeps them in check. In the process of fresh air coming in and diluting the concentration of pollutants and carrying them away.

You might be thinking: “but this is about vent-free appliances.”

Well, ventilation happens indoors too.

Most buildings aren’t perfectly airtight. Outside air comes in through tiny holes in windows or the roof. And pushes the inside air out.


What Types of Ventless Gas Fireplaces are Available?

There are plenty of beautiful ventless gas fireplaces available.

We’ve seen plenty that fit just about anyone’s style. You can have one that’s built in, like a traditional stove.

Or have one that’s two-sided that you can see through. Or even set it up outside.


Built In

Built-ins are popular for customers who enjoy sleek, modern designs.

You won’t have anything sticking out of the wall. They’re installed flush along the wall.

There are lined and unlined styles so you can easily find a style that fits with your decor to create a nice, welcoming space.

Two Sided

Two-sided fireplaces are actually my favorite because of how they look. Just as the name implies, they can be installed in a wall and enjoyed in two rooms.

And they’re pretty versatile, too. So with the stainless steel frames liners, they can be installed outside.


We’ve seen a lot of customers have a ventless gas fireplace designed outside on their patio. You can buy a ventless stove that you like and have it installed outside, depending on the material.

Just like I mentioned with the two-sided fireplaces, you’ll want to find one with stainless steel to allow them to withstand the elements outside.


Ventless gas inserts can add a final, cohesive touch to your fireplace. There are two main types: inserts with logs and inserts with contemporary glass. 

Log Inserts

These look realistic, just like a wood-burning fire. And it adds a traditional feel to the fireplace with modern conveniences.

Luckily, and unlike traditional wood stoves, having ceramic gas logs require minimal upkeep and maintenance.

They’re easy to install, though you want to be sure to have them professionally installed.

Contemporary Glass Inserts

These are popular because they can come in multiple colors and different styles. We’ve seen regular fire glass, reflective fire glass, and even fire gems or rocks.

These can add a modern, colorful touch to your home.

Ventless Gas Fireplaces vs. Other Types of Fireplaces

When it’s cold outside, there aren’t too many things better than sitting around a fireplace.

And if you don’t have a fireplace, you’re probably looking at having one installed for you.

This section goes over the pros and cons of different fireplaces that you can have installed in your home. This way you can make the decision based on the comparison.


Wood Burning Fireplaces

Traditional wood-burning fireplaces have been around for centuries. They usually consist of a brick or metal firebox (where the fire is) and a chimney. 

These produce smoke, of course. 


  • Fires are long-lasting if they are fueled properly
  • It’s easy to find wood chips and logs
  • The scent of a traditional fire is comforting
  • They are commonly found in many older homes


  • Most of the heat created by the fire will be lost, so they are not energy-efficient
  • They require regular maintenance to remain safe and functional
  • The smoke and emissions produced can be harmful
  • Some homeowners associations have banned the use of wood-burning fireplaces

Electric Fireplaces

While electric fireplaces don’t produce a real flame, eclectic fireplaces will keep you warm and give you a nice ambiance added to your home. 

Some even come equipped with the option to change the color of the flame.


  • You can install them yourself, and they can be moved from room to room
  • They don’t burn any form of fuel, so they don’t produce any scent or ash
  • Some models are capable of heating small rooms
  • They are safe for pets and small children because there is no real flame


  • They can cause an increase in your electricity bill
  • They won’t provide heat or light during a power outage

Vented Gas Fireplaces

Just like ventless gas fireplaces, vented fireplaces need a gas line to connect the fireplace to the natural gas or propane reservoir.

Because they need a vent, they are actually better for homes with a chimney and vents.


  • The cost of fuel is very inexpensive compared to solid fuels like wooden logs
  • They can warm your entire home depending on its size 
  • Many different designs are available, so you’ll find something to suit your style
  • There are remote controlled and continuous flame options available


  • As with wood-burning fireplaces, they lose heat through the vent and aren’t energy-efficient
  • Chimneys and vents need regular inspections to remain operational
  • Unless your home has a pre-existing venting system, one will have to be installed

Alcohol Fireplaces

We don’t see these often at all.

Alcohol is one of the cleanest burning fuels available and produces a substance similar to human breath that contains primarily water vapor and carbon dioxide.

There are no gas lines, so they can be installed anywhere. But you’ll need to have additional fuel on hand.

They come in gel or liquid form, and are made of isopropyl alcohol and ethanol alcohol.


  • Alcohol is a clean-burning fuel, so they are eco-friendly
  • They do not require a vent or chimney
  • Since they don’t require vents or gas lines, they are portable
  • They don’t produce any waste like ash or creosote


  • Alcohol is more expensive than natural gas
  • You will need to use more alcohol to heat your space because it doesn’t get as hot as gas
  • Alcohol gels and liquids are not as readily available as other fuels

Water Vapor Fireplaces

We don’t see these often, either. Water vapor fireplaces don’t require a vent or chimney. They operate using tap water and electricity to release a mist into the air.

These are really cool and helpful with pets and small children because the flames produced by the water vapor fireplace are actually cool to the touch.


  • They can be installed anywhere because they don’t require a vent 
  • They produce the most realistic imitation flames
  • Because the flames are cool to the touch, they are safe for pets, children, and commercial spaces
  • Water vapor fireplaces don’t produce harmful emissions


  • Because they run on electricity, they can’t operate during power outages
  • They don’t produce any warmth, so they are ineffective as additional heat sources

Ventless Gas Fireplaces

A 20,000 BTU fireplace can heat up to 1,200 square feet. And because most don’t require an electric pilot light, they’re a great addition to your home during any power outages.

However, there are a few downsides that you’ll need to consider before installing a ventless gas fireplace in your home.


  • Because no heat escapes through a chimney, they have up to a 99% efficiency rating
  • Aside from an optional annual checkup, which shouldn’t cost more than $150, they require very little maintenance
  • They can be installed both indoors and outdoors
  • Ventless gas fireplaces don’t produce any waste like ash or creosote
  • Modern models come equipped with built-in oxygen and carbon monoxide sensors


  • Some people are sensitive to gas fumes
  • Some  states and municipalities have banned the use of ventless gas fireplaces
  • If your ventless fireplace uses propane, refills can be quite costly
  • Because gas burns hot, they may not be suited for small  spaces

How to Choose the Right Fireplace

Before you install a ventless gas fireplace, there are several considerations you need to think of. First, you need to pick the right size. This comes down to the BTUs required to heat the space.

Then, you’ll need to think about if there are any restrictions in your state.

Still, there are some other questions you’ll need to ask to make sure this is the right move for you and your family.


Choosing the Right Size

It’s important to size a ventless fireplace for the size of the foom.

A large, open space, such as a great room, should handle a fireplace with a 25,000 BTU or higher output.

For smaller rooms, such as your bedroom or bathroom, ventless fireplaces can be sized down to only 5,000 BTUs.

What is a BTU?

Before we get too far into the thick of this section, I need to let you know about British Thermal Units (BTUs). This is an international energy measurement, not just for the Britons.

Basically, a BTU is the amount of heat needed to raise one pound of water 1 degree F.

Sounds like an odd requirement, but knowing the amount of heat and energy is necessary to keep your home comfortable.

The easiest way to figure out the BTUs needed is to take a look at the square footage of the space you want to heat. In warmer climates multiply this number by 10-15. In moderate climates multiply it by 20-30. In colder climates multiply by 30-40.

For example, if you’re trying to heat 1000 square feet in a cold climate, you’re looking at 30,000 to 40,000 BTUs to warm the air in your home.

But to help you out, we’ve also put together this chart:

BTUs for 8 foot Ceilings

12-ft Length18-ft Length24-ft Length30-ft Length36-ft Length
12-ft Width5,18847,77610,36812,96015,552
18-ft Width7,77611,66415,55219,44023,328
24-ft Width10,36815,55220,73625,92031,104
30-ft Width12,96019,44025,92032,40038,880
36-ft Width15,55223,33831,10438,88046,556


BTUs for 10 foot Ceilings

12-ft Length18-ft Length24-ft Length30-ft Length36-ft Length
12-ft Width6,4809,72012,96016,20019,400
18-ft Width9,72014,58019,40024,30029,160
24-ft Width12,96019,44025,92032,40038,800
30-ft Width16,20024,30032,40040,50045,600
36-ft Width19,44029,16038,88048,60058,320
These are basic estimates and the actual BTUs you’ll need depend on several other factors:

  • Number of windows
  • The climate
  • Age of the building
  • Orientation to the south
  • Type of and amount of insulation
  • Construction techniques
  • And more

When you are calculating the BTUs you’ll need for your whole house, you need to include the worst-case scenario. Which means that you should account for the coldest that it will get.

For example, maybe the coldest it will ever get is -30 degrees F. And maybe that happens once every 3 years. You’ll want to make sure the BTUs you are accounting for considers that huge outlier.

There are a few more things you’ll need to consider to will help determine the BTU range, hopper capacity and size of the pellet stove you’ll need.

BTU Code Restrictions

Vent free appliances are also subject to more codes than vented units, with BTU output limits and installation requirements. 

Vent-free fireplaces are limited to a maximum of 40,000 BTUs per hour for most installations, with the lower limit of about 6,000 for a bedroom or bathroom installation. 

This restriction on bedrooms and bathrooms is absolute, no matter the size of the room itself. 

When the time comes for an inspection, a violation of this code will cause your home to fail the inspection. 

The National Fuel Gas Code had determined that vent-free appliances cannot be installed in what they term as a confined space, defined as a room with less than 50 cubic feet per 1,000 BTUs per hour. 

Cost of Ventless Gas Fireplaces

The cost of the firebox unit or insert and the log assemblies are roughly the same for both ventless and vented gas fireplaces.

Both require the same type of gas or propane connection. The cheapest way to have a ventless fireplace is with gel-based units. No plumbing is required and they’ll burn up to three hours.

The major price difference is the cost of venting. Since you don’t have to worry about that with ventless, you’ll still look at $1,000 to $5,000.



Gas- or propane-connected ventless fireplaces usually include a factory-finished enclosure or mantle.

With professional installation, you can expect to pay between $2,000 and $6,000.

Installation may not require a permit, but you should check with your local building department to confirm if there are any regulations or limits on the use of a ventless fireplace.

Gel powered ventless fireplaces cost less and don’t require professional installation and associated costs. They cost $300-$700.

You’ll need to assemble some of the units, including putting the factory-supplied logs in front of the gel canister.

The fuel comes in 13-ounce canisters that usually cost about $3 and last 2.5 hours each. They’re sold in 24 packs for $80. Or you can buy a dozen 30-ounce refill bottles for $110.

Electric fireplaces are standalone, self-contained, and factory-finished. So there’s no installation other than removing them from the box and plugging into the wall socket.

They cost about $1,000 on the lower end and depend on how sophisticated the mantle will be.

Final Tips before Buying

Despite the name, they’ll still vent unburned combustion byproducts into your living space. Traditional fireplaces exhaust combustion byproducts out of your home through a flue.

You’ll also see other moisture-related problems, such as mold. To combat these issues, the manufacturers have added safety measures.

But there are still issues with carbon monoxide, HUD, and insurance.

This section will explore each of those.


Carbon Monoxide Dangers

To mitigate the carbon monoxide (CO) dangers, manufacturers often instruct customers to keep a window open while using the fireplace. 

This is easy to ignore, especially when it’s cold out. You don’t want to heat the whole neighborhood, do you?

Most manufacturers have installed an oxygen-detection sensor (ODS) in their ventless fireplaces that will automatically shut down the appliance if oxygen levels become too low. 

The issue here is that the ODS is on the lower part of the unit, near the floor, where it detects cool, fresh, oxygen-filled air and misses the hot combustion gasses as tehy rise and pool toward the ceiling. 

And if the sensor fails, any CO-producing abnormality will go unnoticed and could harm you and your family. 

That’s why many states have simply outlawed ventless gas fireplaces altogether. Many municipalities, too. 

Furthermore, ventless fireplaces have been advised against by various groups, such as American Lung Association, the Centers for Disease Control, the Environmental Protection Agency, and even the Mayo Clinic

In particular, these organizations warn against exposure of people with extra vulnerability to CO, such as kids, pregnant women, elderly, and those with pre-existing cardiovascular difficulties. 

I should also mention that there haven’t been any documented cases of fatalities caused by ODS-equipped ventless fireplaces, according to the US Consumer Product Safety Commission.

US Department of Housing and Urban Development (HUD)

In addition to the restrictions mentioned above, the HUD has banned the installation or use of ventless fireplaces in HUD housing. The HUD Handbook (7485.2) states the following:

(1) Individual Gas or Oil Heaters. Individual gas and oil heaters shall be connected to an approved vent, flue or chimney, and shall have adequate air supply for complete fuel combustion.

Heaters shall be protected to prevent unsafe human contact or fires and have clearances around them.

Floors beneath equipment shall be protected against fire and deterioration. Screening shall not minimize required ventilation to the space heater.

When provided new or replaced, individual controls or units shall not be positioned near the floor, especially in elderly projects or in units for the handicapped.

(2) Open Flame Heaters. Open flame radiant space heaters shall not be used.

Get Insurance Approval

Adding any type of extra heat to your home can slightly increase your insurance rates. But not informing your insurer can void your coverage completely in the event of a fire. 

So before buying a ventless gas fireplace, obtain a clearance diagram and installation specifications from your insurance company. 

This will detail the amount of space you need to provide between your fireplace and nearby furniture, floor coverings, draperies, and walls. 

Follow these installation guidelines and return the form to your insurance company for approval. Keep in mind that your insurer will be more likely to approve the installation if it’s done by a professional. 

They’ll likely also want it inspected before approval is given. 

Additionally, as I’ve already mentioned, every area has fire and building code restrictions. Be sure to review and follow these guidelines. 


It is strongly recommended (and in some places, required by code) that you have a gas specialist install your vent-free appliance. 

Each fireplace has very distinct and detailed installation instructions, since the logs must sit in a precise location on the burner. 

And the burner must be thoroughly examined and tested for proper orientation. 

Simply put, everything must be in perfect order to prevent issues with oxygen depletion, carbon monoxide emissions, soot, etc.


It is strongly recommended (and in some places, required by code) that you have a gas specialist install your vent-free appliance.

Each fireplace has very distinct and detailed installation instructions, since the logs must sit in a precise location on the burner. 

And the burner must be thoroughly examined and tested for proper orientation. 

Simply put, everything must be in perfect order to prevent issues with oxygen depletion, carbon monoxide emissions, soot, etc. 

Maintenance – Even though installation is relatively easy, ventless fireplaces aren’t a turn-them-on-and-forget option. 

All units will require at least annual cleaning of the log set and other exposed components. 

While gas and propane products should have the oxygen and CO monitors checked and adjusted annually for optimal performance. 

Ventless fireplaces should be annually inspected for the following safety defects:

A gas leak – During production, installation, or servicing, a leak can be created

Plugged burner ports – The contractor may accidentally plug the burner ports while spreading ceramic tile over the burners, or they may be painted over at the factory. The resulting unbalanced burn will create excessive carbon monoxide

A clogged burner – Dust, carpet lint and pet hair can gradually choke off the fireplace’s air supply, leading to incomplete combustion and high amounts of CO that are vented into the living space

High gas-input rate – Excessive CO ventilation or overheating of the unit will result from firing the gas higher than the input rate set by the manufacturer’s specifications. 

This can be caused by high gas-supply pressure, an incorrect orifice drill size done at the factory, or if the installer gives the customer’s unit a larger flame for aesthetic reasons

A cracked burner – The gas burner may develop a crack over time and function erratically, producing high levels of CO;

The fireplace contains items other than the artificial logs designed for the unit – Problems caused by the incineration of firewood or other flammable items will be immediate and extreme. 

A more likely and less obvious hazard is created by adding pebbles, lava rocks, and other non-combustible aesthetic touches to the fireplace, as their exposure to flames will cause an unsafe rise in levels of CO

A missing or defective ODS – As these components may fail, it is advisable to install a CO detector near a ventless fireplace and, ideally, in other rooms, as well.

Quick Tips for Hiring a Chimney Company

When you’re ready, you should schedule a time for a certified chimney expert to go to your home to take a look at the area you want your ventless fireplace installed.

You can easily reach out to your local chimney company and have a done-for-you solution in no time!

But navigating through all of the chimney companies in your city can be a chore all on its own. And it makes sense, too.

Hiring anyone to come into your home to install a heat source involving fire shouldn’t be a task you take lightly. So I created a list that you can use to make sure you make the right decision when you need someone to help you in your home.


How to Hire, What to Look For

When you’re hiring a chimney company, you should always ask the following questions before allowing them to come into your home:

  1. Can the company provide references? 
  2. Does the company carry a valid business liability insurance policy? 
  3. Does the company ensure that a certified chimney technician will be on the job? 

If they guarantee all three of those, then you are in a good spot. The technicians don’t necessarily need to be certified by the CSIA, but I do recommend putting in a bit more due diligence before accepting a certification that’s not by the CSIA. 

This is because certifications are a tricky thing, especially in an unlicensed industry like ours. Any company can craft a list of job-related questions and sell them as an exam and certify those who pass. 



I recommend you take a few extra minutes in your research before making your hiring decision to learn more about the certification the company has. Here are a few tips to make sure the certification is reputable:

  • Is the word “certified” just part of the business name or is it an earned designation?
  • Is the certifying body a for-profit business or non-profit?
  • Does the certification need to be maintained and renewed through continuing education as the industry evolves, or is it well enough to be certified through a one-time exam?
  • Is the certifying body well-established or are they relatively new to the scene? New doesn’t mean “bad” but you should make sure the requirements for certification are more or at least equally stringent as those of more established certifications
  • Is the mission statement of the certifying body focused on educating and protecting homeowners or is it more focused on making it easier to earn a certification?
  • Does holding the certification require following a code of ethics?

If you can answer all of these questions, then I think it will be safe to allow the company in your home to work on your chimney.

Besides, it’s probably cheaper for them to buy a cap at the dealer discount than for you to buy one at retail cost.

It doesn’t matter if you are in Roanoke, Lynchburg, Blacksburg, or some other city anywhere in the USA — if you have any questions about the safety of hiring a chimney company, please don’t hesitate to email me at or call me at 540-225-2626. I’m happy to help!

Final Thoughts

Patriot Chimney has a few CSIA Certified Chimney Sweeps that you can trust with your home and family. During your service, you can expect your technician to inspect your chimney with a video camera so we can give a full top-to-bottom, inside out inspection. 

We’re licensed, insured, certified, and guarantee you’ll be happy with your service.


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