How to Pick Out a Ventless Gas Fireplace

Ventless gas fireplace decorated with surrounding bricks, houseplants and couch

The Spruce / Ana Cadena

Even though few homes today rely on fireplaces as their primary heating source, many homeowners still enjoy the ambiance of a warm fireplace. Ventless gas fireplaces are popular because they're clean and easy to use. They are designed to burn gas more efficiently than vented versions, resulting in far fewer fumes and no need to install a flue. However, reviews are mixed about their safety.

Read on to see if ventless gas fireplaces are suitable for you—some states have regulations banning their use, and others have certain restrictions. This comprehensive guide will help you make the best decision regarding using ventless gas fireplaces in your home.

What Is a Ventless Gas Fireplace?

Also known as an unvented or vent-free fireplace, a ventless gas fireplace operates with natural gas or liquid propane (LP) that flows into a gas burner mounted in the fireplace. When ignited, the flames run through gaps in artificial ceramic fiber logs, giving the illusion of a real wood-burning fireplace.


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Before Buying a New Ventless Gas Fireplace

Although they have safeguards built into new ventless gas fireplaces, their safety is debated. A patchwork of regulations across the United States controls the legality of ventless fireplaces. Roughly a third of states allow these units with no restrictions. California and Massachusetts have banned all ventless fireplaces indoors.

In the remaining states, regulations vary based on the city's population, altitude, and surrounding geography. And many states have restrictions on where in the home you can install a ventless fireplace—for example, they may not be allowed in sleeping areas.

Ventless fireplaces are engineered to minimize exhaust fumes. A special regulator creates a fine mixture of gas and air that burns cleanly, and the units are carefully tested in approved laboratories before they can be sold. Although fumes are significantly reduced, ventless fireplaces still release small amounts into the home, increasing the risk of carbon monoxide exposure. Also, non-vented burning of natural gas or propane produces water vapor as a byproduct, increasing humidity levels and the risk of mold.

Review the unit's specifications to ensure it meets safety standards and is approved for installation by your local building codes. Ventless fireplaces can be a good choice for a decorative feature in a room where you can supervise its use, but don't count on them as a principal heat source, especially in a sleeping area. Also, avoid using ventless fireplaces if anyone in your home suffers from breathing problems, such as asthma or COPD. Some manufacturers recommend leaving a window cracked open while operating the fireplace to ensure there is a source of fresh air.

Buying Considerations for a Ventless Gas Fireplace


Ventless fireplaces can accommodate small and large rooms and outdoor spaces. Various styles can suit your room, including see-through or two-sided models. You can get custom-made fireplaces to fit your space or fireplace inserts for use in place of an old fireplace.


They are made of many different finishes and designs, usually lined with stainless steel, cast iron, or other fireproof material. They operate with natural gas or liquid propane. Some even use alcohol gel cartridges, similar to Sterno cans. Most use artificial ceramic fiber logs to give the illusion of a real wood-burning fireplace, lava rock, or colored fire-safe glass pieces. Some log sets come with wood-style grates, glowing embers, or sand granules for placement beneath the logs themselves. Unlike other fireplaces, ventless gas fireplaces do not have any doors enclosing the unit since they require ambient room air to fuel the gas flames.


Each space has a maximum heat allowance based on its size. Average sizes range from 12 inches to 42 inches, although you can find much longer, like 72 inches. The heat output can vary from 20,000 to 40,000 British thermal units (BTUs). To figure out the maximum BTUs for a room, multiply the room’s length, width, and height to get the cubic feet of the room. Then multiply by 20. For example, if a room is 1,400 cubic feet, it should not radiate more than 28,000 BTUs. When buying ventless gas log sets, it lists requirements for the firebox space and gives specifications.

Safety Features

A well-insulated home can sometimes have lower oxygen levels, causing a slow indoor and outdoor air exchange. Many ventless gas fireplaces have an oxygen detection system, which automatically turns off the unit if oxygen levels in the room fall below a certain level. The fireplaces may also have built-in carbon monoxide detectors that automatically shut off the fireplace if high levels are detected.

Special Options

You can ignite most ventless gas fireplaces via a switch or the push of a button on the fireplace or the remote control. Many come equipped with automatic ignition, eliminating the need for a constantly standing pilot light. Some also have backup battery mode in case of a power outage. In many cases, you can control the size of the flame and reduce gas usage.

Types of Ventless Gas Fireplaces


Built-ins are custom-fitted for the space you have. A majority are pre-fabricated, and they come in many sizes by fireplace manufacturers. This type is best for newly built homes, full-home renovations, or room redesigns. They come in one or two-sided (or see-though) versions. The two-side type is placed in a dividing wall between two rooms.

Ventless Gas Fireplace Insert

A ventless gas fireplace insert is an enclosed box that fits inside of your fireplace. It helps trap heat and contains the flame. Like built-ins, the fireplace box reduces air leaks, is smokeless, and lowers energy bills by keeping heat inside instead of venting it out. This option is a good bet if you want to repurpose your existing fireplace but don't want smoke in the house or your flue isn't operational.


Outdoor ventless gas fireplaces need to withstand the elements and are designed to be weatherproof. They are made of more durable materials and use stronger flames that won't get blown out by the wind.


The cost of the firebox unit or insert and the log assemblies are roughly the same for both ventless and vented gas fireplaces. Because venting is such a large part of the installation cost, ventless fireplaces are generally a lot less expensive than vented units. A vented gas fireplace costs between $3,500 and $8,000 to purchase and have installed, depending on the amount of carpentry required to run the ductwork. By contrast, a ventless fireplace costs between $1,000 and $5,000.

Both require a natural gas or propane connection, so there is no cost difference in terms of plumbing. If you want to save some money and forego the gas line, you can get a ventless fireplace that uses gel canisters for fuel. No plumbing is required, as these units use alcohol-based gel fuel canisters that burn for about three hours.

The biggest variance in price reflects different sizes, materials used, and whether the unit is custom-built and designed, prefabricated, double-sided, or an insert. The inserts are the least expensive option; you can find some nice ones for about $500 to $800. Although, you would need to also factor in additional labor costs to hook them up.

How to Choose a Ventless Gas Fireplace

Before deciding on a ventless gas fireplace, take a look at vented fireplaces, wood-burning, and electric-run fireplaces before you make your final decision on going the ventless gas route. It might be your best option but explore the rest too.

Vents vs. Ventless

In a traditional vented gas fireplace, two vents run outside. One is a fresh-air intake that provides combustion air to help the gas burn more efficiently. The other vent safely removes any natural gas or propane exhaust gases to the outdoors.

A ventless gas fireplace looks quite similar to a vented fireplace on the surface. It has a control panel that operates the pilot light, flames, and holes in ceramic artificial logs for the flame jets. There is a slight difference in the flame jets between the two styles, and as a result, ventless fireplaces tend to burn somewhat less realistically than vented units. As with a vented fireplace, ventless units usually have blowers that circulate air around the firebox to heat the room.

Ventless fireplaces do not have two outdoor vents. Instead, combustion air for the burner is drawn into the fireplace from the air inside the home, and exhaust fumes also remain inside the home. This may sound dangerous, but ventless gas fireplaces are deemed to operate within the range of safety for cycling these combusted gases back into the home's interior, similar to how a gas stovetop works. By contrast, vented gas fireplaces create a dangerously high combustion exhaust and therefore must be vented to the outdoors.

  • Requires venting installation

  • Exhaust gases can backdraft into the house

  • Burns more realistically

  • Not banned in any states

  • Fuel costs are higher

  • Not as expensive to install

  • No backdrafts

  • Can produce water vapor and potential mold issue

  • Has many safety features

  • Warmest and more energy efficient

Wood-Burning or Not?

Wood-burning fireplaces require a fully operational flue, firewood, kindling, tinder, safety-strike matches, an iron fireplace grate, and a poker. The ambiance, cracking sounds, and smell of a real-wood burning fire is a unique experience. However, smoke, ash, and soot from fires can be dangerous for people with respiratory issues, and backdraft issues can increase carbon monoxide levels inside. If using a fireplace for a source of heat for the home, wood-burning fireplaces are inherently energy-inefficient since a good deal of the home's heat inevitably escapes up the flue rather than radiating into interior spaces.

Vented Gas Fireplaces

Vented gas fireplaces are somewhat better at retaining heat, but modern homes are now being built so airtight that a vented gas fireplace may create negative air pressure that hinders good exhaust. Air flowing out a chimney vent flue can even prevent combustion gases from other appliances from exhausting properly.

Electric Fireplaces

An electric fireplace is an electric heater that mimics a traditional wood or gas-burning fireplace. There are no flames, no gas lines, only an electric plug. Electric fireplaces can be placed on a wall or inside conventional fireplaces no longer used to make fires. Most have LED screens or dimming lights to mimic a crackling fire. An electric fireplace is the safest option for people who have breathing issues. This fireplace is the most inexpensive of the alternatives.

Are Ventless Gas Fireplaces Your Best Option?

Gas fireplaces with no vents passing to the exterior are becoming more popular for remodeling work and new construction homes. Ventless fireplaces are easier to install than vented wood or gas fireplaces and warm rooms nicely. Because there is no airflow to the outdoors, they do not create the negative pressure problems that can occur with a vented fireplace. They do not emit as much exhaust as wood-burning fireplaces and might even be safer than vented gas fireplaces. But, if you have a respiratory illness or a very tight budget, electric fireplaces will remain your safest and most affordable bet.

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Where to Buy

You can buy ventless gas fireplaces from brick-and-mortar fireplace stores, home improvement big-box stores, and online. Specialty stores may also sell outdoor kitchen supplies and barbecues, or only handle fireplaces. Major home improvement stores also carry several lines of fireplaces of all types. Your most extensive selection will be online; however, a fireplace store will likely have the most knowledgeable staff, many samples to show you, and the largest selection. Also, if you are building new construction, you can consult with your architect and builder to determine the best fireplace for your new space and ask them to source the fireplace through their connections.

Buying In-Store

When buying in-store, describe your home and the look and feel you want to convey with your fireplace. Also, note if you want the fireplace to be a heat source or for purely aesthetic reasons. Bring the measurements for your wall space.

A professional can help you narrow down your choices. Also, ask about delivery times, how long it takes to install, and if you need to run a gas line to your fireplace. The costs can mount quickly, especially if they need to break into the walls.

If you install this during a full-room renovation or new construction, your costs should be more straightforward and part of the home construction costs. Still, in many cases, you will likely require a licensed HVAC professional or plumber to complete the installation to ensure the heating capacity doesn't exceed manufacturer requirements and complete the electrical wiring for the ignition.

Also, ask if the fireplace and parts have a warranty. Some fireplaces have a lifetime warranty on the firebox; others may only warranty the ceramic logs.

Buying Online

Online you can find the most variety, and in most cases, you can comparison shop for the best prices. If buying through a web-only fireplace store, most have fireplace professionals waiting for a phone call to answer most of your questions, much the same as if you were in the store.

The biggest drawback with online buying is that you cannot physically see or knock the tires on the floor models. Since you are dealing with an online vendor and this is an expensive purchase, make sure that it can be returned without any hassles if it arrives and is not exactly what you want. Also, review delivery windows, delivery costs, and installation options. If they don't do the installation, they can likely point you in the direction of a service partner who can.

You can also buy through Amazon and Wayfair and might find some decent pricing, but you may not get any assistance if you have particular product questions. You can comb through the question/answer section on the product page and read the reviews for clues about customer feedback, satisfaction, and quality issues; however, it's a gamble.

Where to Buy a Gas Fireplace Insert

A gas fireplace insert is a great choice when retrofitting an existing fireplace or creating a custom gas fireplace feature; these inserts offer a variety of installation and fuel options. If it serves your needs, matches your look, and fits your space, then an insert is a perfect way to go.

  • Is a ventless gas fireplace worth it?

    A ventless gas fireplace is one of the most energy-efficient fireplaces that closely mimics the look of a wood-burning fireplace—without producing smoke, ash, or soot. They are also more energy-efficient than vented fireplaces because no heat escapes up the flue, so you'll save money on your gas bill.

  • Can you put a television above a ventless gas fireplace?

    You can mount a TV above a ventless gas fireplace, but to make sure you don't damage it, make sure a mantle above the fireplace shields the heat from traveling up, and you can build a little nook into the wall to recess the television safely within. Height clearances for each fireplace vary depending on manufacturer instructions.

  • Does a ventless gas fireplace have an odor?

    In a gas ventless fireplace, oxygen is provided by the air in your home. If that air contains impurities, like pet hair, dust, and smoking, it can produce odors that get amplified by the flame. Avoid those odors by vacuuming debris and using an air purifier unit.

  • How do vented gas logs work?

    Ventless gas logs release heat (and moisture) into the same room and recirculate the same air back into the room.

  • How do you clean a ventless gas fireplace?

    Each unit is different, but in general, since ventless gas products are carefully engineered to have minimal soot and fumes, the burner assembly and combustion chamber must be frequently cleaned to keep it safe for home use.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Ventless Fireplace Inspection. International Association of Certified Home Inspectors. 

  2. Inspecting Unvented Combustion Appliances. International Association of Certified Home Inspectors.

  3. Carbon Monoxide Poisoning: Unvented Gas Space Heating Appliances (AEN-204). Iowa State University.