Ventless gas logs burn natural gas or liquid propane within a self-contained firebox. They do not release emissions through a chimney or flue. This type of home appliance first came out in 1980, and remains controversial to this day.
Building a chimney and damper for a fireplace can get expensive. The vent-free gas stove requires no chimney, so it appeals to families on a budget. However, the question that first arose when the ventless gas fireplace logs came out was whether it was completely safe. That question remains unanswered.
In this post, you will learn:
- How a vent-free fireplace works
- What are vent-free gas logs?
- What a vent-free gas log set sound like
- What a vent-free gas log set smells like
- How ventless logs affect air quality
- Why correct sizing is essential
- How to maintain the appliance
- How ventless gas-burning heaters are regulated
- The pros and cons of unvented gas or propane heaters
- Better options in ventless heating
A ventless gas fireplace must burn more efficiently than vented models. This eliminates most harmful emissions. It must meet strict federal safety standards that limit emissions within the home.
In general, a supply line delivers fuel to the ventless gas logs. Upon ignition, a fuel and oxygen mixture catches fire. The flames emerge through openings in the gas log set in the firebox, simulating a wood fire.
Ventless gas logs draw and consume oxygen from the air in the room. Once the flames in the firebox heat the air, it returns back into the room. The heated air contains water vapor and a small amount of carbon monoxide from combustion.
However, a vent-free gas fireplace has specialized technology to keep harmful emissions low. It has a regulator to create a precise mixture of oxygen and gas for the cleanest burn possible. Some of these appliances use catalytic converters to remove most of the volatile organic compounds from the heated air.
Many brands of gas fireplace logs also come with smartphone remote control capability. This further promotes efficiency because the owner can adjust or deactivate the product as needed from any location. This helps lower fuel consumption.
A programmable millivolt thermostat also supports fuel efficiency. You can set it to turn off the heater when everyone is at work or school during the day.
A millivolt thermostat, as part of a smartphone remote control system is also energy efficient. It only requires minimal electricity.
Most non-wood burning fireplaces have artificial logs that mimic the look of a wood fire. Gas fireplaces typically have logs made from ceramic fibers or a mixture containing cement.
One advantage of this type of gas log set is that it is non-flammable and refractory, or heat resistant. Most are quite durable, too, and some fiber logs even have steel reinforcement hidden inside.
They help with heating too. Because it is refractory, each gas log absorbs heat during combustion without damage. Then, it releases heat into the room once the appliance is off.
In addition, manufacturers can shape, texture and color a ceramic fiber gas log set as they wish. For example, they could fashion the gas log set to look like red oak or split oak logs. This helps in achieving the realistic look that homeowners prefer.
When this appliance turns on, whether automatically or with a remote control, you will likely hear a click. You will hear a whoosh as the flames ignite, and then a rush of air as the fan engages. The ventless gas log set itself burns quietly once it gets going. Depending on the model, though, the fan can be noisy.
When you first fire up a new ventless, gas-burning heater, it emits a chemical smell. It is burning off some of the factory residue and curing the logs.
Manufacturers recommend running a ventless fireplace at high heat for several hours the first time you turn it on. They also suggest opening the doors and windows to let the unpleasant odors and chemical vapors escape. With a vented heating appliance, these fumes would automatically go up the flue instead of polluting your home.
After this initial curing, chemical odors should be minimal when you run your ventless stove. However, that is not always the case. It can take several sessions before unpleasant smells fully burn away.
There are three major ways that ventless logs affect the air quality inside your home:
1. They draw oxygen from within the room for the combustion process.
If your home has adequate ventilation, chances are good you won’t notice an oxygen deficit while your gas stove is on. In a closed room, though, the supply of oxygen may fall below an acceptable level when your stove has been running for a time. This can cause headaches and breathing difficulties.
This happens often enough that some manufacturers suggest you open a window while your fireplace is running. So two points here: if a window is open, your fireplace is no longer vent-free. If the weather is wintry, opening a window lets out the heat that you are trying to keep inside.
What’s more, to be certified by the American National Standards Institute, ventless heaters must have oxygen deficit sensors, also known as ODS. These sensors shut off the heater if the oxygen level in the room drops below 18.5 percent. The normal level is 21 percent.
2. They emit any carbon monoxide left over from combustion back into the room.
Carbon monoxide is a by-product of the combustion process in fireplaces and internal combustion engines. If it builds up to a toxic level – 1 percent or above – in your home, it can kill family members and pets in minutes.
CO is impossible to see or smell. If you are asleep or otherwise incapacitated, you won’t even know about it before it’s too late. Otherwise, the following symptoms may alert you that CO has built up to a dangerous level:
● Chest pain
Manufacturers suggest that owners of vent-free single or dual fuel fireplaces set up CO monitors as well. These devices sound an alarm if they detect levels are high. Many states and local codes already mandate CO detectors in residences.
3. Ventless gas logs also emit moisture into the room.
A ventless gas log set cannot expel emissions up the chimney. It cannot get rid of the moisture leftover after combustion, either, except by releasing it into the room.
Inside a gas fireplace, fuel and oxygen ignite. The fire consumes the gas, creating water and carbon dioxide waste in the process. One molecule of gas burned in combination with five molecules of O2 yields three molecules of CO2 and four molecules of H20.
When a vented appliance exhausts CO, smoke and particulates to the outdoors, the moisture goes too. When a non-vented gas fireplace blows heated air into a room, that air contains all the moisture from the combustion process.
Excess moisture can cause damage and mold or mildew growth. In a warm room, the moisture from ventless gas fireplaces condenses on the walls and ceilings. It potentially damages paint, wallpaper and wood furniture.
Correct Sizing is Essential
A ventless gas fireplace does not have a chimney. It must be the right size for the room. If the gas log set is too small, it won’t provide enough heat. If the unit is too large, it will use more oxygen and emit more toxins than necessary.
To be as safe as possible, a vent free stove should have a BTU rating that fits the square footage of its location. In general, an output of 15,000 BTU or above is appropriate for a large space such as a great room. A vent-free heater that produces 5,000 BTUs or less is safer for small areas like a dining room or home office.
For example, a dual fuel ventless gas insert from Duluth Forge produces up to 26,000 BTUs. It is sized for spaces up to 1,350 square feet. In contrast, the 15,000 model from Duluth Forge heats up to 600 square feet.
Regular Maintenance for Safety
Regular maintenance is part of owning a gas-burning, ventless appliance. It requires a thorough interior cleaning every three months. This includes keeping the air and fuel injector holes free of dust and particulates.
If these holes are fully or partially blocked, it affects the unit’s efficiency. The combustion process will be incomplete, resulting in soot buildup. Incomplete combustion can also increase deadly carbon monoxide emissions.
Regulations for Ventless Gas Logs
Two out of fifty states, California and Massachusetts prohibit or strictly limit the installation of vent-free gas heaters due to safety concerns. Also, federal regulations ban installation of ventless gas-burning heaters in all HUD housing.
Some large cities in states such as Texas and New York prohibit ventless gas heaters. In other states, local jurisdictions require certification from professional installers before permitting these appliances.
Pros of Owning a Vent Free Heater
● No need for a chimney or vent
● Clean burning/energy efficient
● Can go on interior as well as exterior walls
● Governed by laws, safety guidelines, certifications and building codes
Cons of Owning a Vent Free Heater
● Consumes oxygen
● Emits CO
● Adds moisture to the air
● Questions about safety
Better Options in Ventless Heating
If the data on ventless gas fireplaces concern you, find out about similar yet safer options in heating for your home. These include a vented log set or a non-combustion fireplace.
If your home already has a wood fireplace with a chimney, you can put in a vented gas or wood-burning insert. You won’t have to go to the expense of having a venting system installed.
Vented gas fireplaces provide the ambiance of a real fyre, just like a ventless heater. However, most of the toxic emissions go up the chimney, not into your living space.
You can eliminate fossil fuel consumption, toxic emissions and the need for a chimney with an electric fireplace. This solution is the most popular alternative to a natural gas log set for builders and homeowners alike.
Electric fireplaces don’t require a chimney because no combustion takes place. That means they don’t consume your oxygen or pollute your air. They don’t pose health risks like an unvented gas fire.
The best electric fireplace brands have realistic flames and sound effects. For example, MagikFlame uses HoloFlame technology to produce a three-dimensional, realistic flame. Each model offers a choice of 30 fire styles.
MagikFlame Versus Unvented Gas Fireplaces
Versatility – Free-standing MagikFlame electric fireplaces can go anywhere in a home. It doesn’t matter if it is up against an exterior or an interior wall, because it requires no venting. There’s even a model with a corner mantel package, so it can fit neatly in any nook. Similarly, a ventless gas log set does not need to be placed on an exterior-facing wall.
Fuel efficiency – Both types of unvented fireplaces, gas or electric, convert almost all the fuel they use into their heat output. This means getting high marks for fuel efficiency. However, units that burn natural gas emit a modicum of toxins into the home. MagikFlame does not burn fuel, and it does not emit anything but heat.
Also, it’s important to note that MagikFlame does not need a separate fuel source like a gas burner. You won’t be paying extra for fuel each month. Both types of ventless appliances use electricity, but the MagikFlame system is self-contained.
Convenience – Electric and ventless LP fireplaces share some convenience features. These include remote/smartphone control and programmable thermostats. They heat a closed space more quickly than a central furnace.
In addition, neither needs a vent or chimney, so they can go on any wall or in any room. A gas-burning fireplace must be convenient to a gas line. Also, you do have to take care to match the heat output of a gas log set to the space. Otherwise, oxygen consumption and emissions can be too high.
Ambiance – MagikFlame’s proprietary HoloFlame technology provides the look of actual, three-dimensional flames rising from a realistic log set. You can select one of 30 real fire formats, some with embers, for your flames.
Such styles as Dragon’s Fury and Mid-Century Classic change the look of your fire on demand. Glowing embers among the logs and accurate sound effects of a crackling fire complete the experience.
Because a gas appliance has a stationary gas log set with a flame aperture in each ceramic fiber log, you get one style of fire. You also may or may not be able to hear the sounds of combustion. You won’t see glowing embers because the flames fully consume the fuel.
Appearance – One of the great aspects of the contemporary fireplace market is the creativity of designers. All sorts of styles, including linear, three-sided, and standalone, offer plenty of options.
Classic quality is the hallmark of MagikFlame. You can see it in the designer, furniture-quality wood surrounds that frame each fireplace. Each style features classic lines with artisan details like appliqués and crown molding.
MagikFlame’s refractory electric log set is attractive too. The logs resemble real wood varieties like split oak and red oak.
Maintenance – A non-vented propane gas log set requires regular maintenance. You have to make sure no dust, pet dander, or debris blocks the apertures. A thorough dust-out every three months is compulsory.
MagikFlame holographic infrared fireplaces have sealed fireboxes. They do not require interior maintenance. The company doesn’t even sell replacement parts. It designs its products for years of maintenance-free use.
Of course, you should dust the exterior just as you would any piece of fine furniture. With a modicum of care, the beauty of the real wood surround and mantel will be a focal point of any room for many years.
Installation cost – Both ventless fireplaces that burn fossil fuels like propane and MagikFlame electric fireplaces save you the cost of outdoor venting. The reason behind that savings is different, though.
In the case of ventless fuel-burning units, the combustion chamber burns as cleanly as possible. That means that the byproducts it exhausts into the room are minimal. Therefore, it can operate without a chimney, flue, or damper.
When it comes to a MagikFlame Holographic Fireplace, no combustion occurs. There are simply no byproducts. Instead, you get the appearance of a real fire and the warmth of a fireplace without carbon monoxide emissions. Thus, you won’t have safety concerns.
Additionally, gas fireplace logs require a gas line. If your selected location does not have a hookup, you’ll need a professional to put one in. That adds to your cost.
Environmental impact – Natural gas burns relatively cleanly. However, exploration, drilling, and production of this fossil fuel takes a toll on the environment. Methane, a greenhouse gas that seeps from abandoned drilling sites, is the primary ingredient. Gas seepage amounts to about 29 percent of the U.S.’s total methane emissions.
Since MagikFlame fireplaces do not burn fuel, they do not put the environment at risk. As more and more electricity comes from clean sources such as sun, wind, and water power, the environmental impact of electricity production stays low.
MagikFlame, as a safe, low-impact heating appliance is a natural alternative to vent free gas logs. As the world moves steadily toward a zero-emissions environment, MagikFlame will remain at the forefront of home heating technology.