When purchasing fireplace logs, choose ones that are compatible with the type of gas you use. Although there usually isn't a difference in the actual logs, the burner and valve sets are different depending on whether you use natural gas or propane.
The major difference when it comes to gas logs is whether they are vented or ventless.
Duluth Forge 29.5-Inch Vent-Free Zero Clearance Gas Fireplace with Mantel
Vented gas logs offer the most realistic flame pattern. The flames lick and cloak the logs like a real wood-burning fire. Unfortunately, there's a price to pay for those big, beautiful flames. Vented gas logs (as the name implies) require venting, so you'll need to have a fireplace with a functioning chimney. A good rule of thumb is that vented log sets can only be used in fireplaces that are capable of burning real wood logs. You can't use them in a direct vent or b-vent gas appliance.
The damper of the chimney must be open while the fireplace is in use and this lowers the heat efficiency of the fireplace. Even though you might still feel some cozy heat right next to the fire, it won't be very efficient at heating a larger room.
Ventless gas logs produce such minimal exhaust that they don't need a chimney. They are super heat efficient and are great for adding supplemental heat to your home.
But yes, there's a catch. Part of the reason ventless gas fireplace logs can get by without a chimney is that the flames never actually touch the logs. This lowers the amount of exhaust created, but it also makes the fire look less realistic. Instead of touching the logs, the flame is directed to purpose-built void areas between them. Manufacturers design the log sets and flame cutouts so that it tricks your eyes into thinking that the logs are burning realistically, but the flame aesthetic often isn't quite as good.
Empire Rock Creek Refractory Ventless Gas Log Set (side view)
One other aspect is the difference between how the logs are positioned. Many vented log sets can be arranged in your fireplace in a number of configurations (as long as they have the right airflow and aren't blocking the gas burner). Vent free gas log sets usually have recesses, locating pins, or valleys that ensure they are set up in only one configuration. If you're very particular about arranging logs yourself, you might want to go with the more customizable option.
So there you have it. If you want a fire mostly for the visual appeal (and the option of an extra cozy seat right next to the fire), then vented is the way to go. However, if you want more even, efficient heat, or don't have a chimney option, ventless logs rise to the occasion.
What Are Gas Fire Logs Made Of?
Gas logs are made by pouring concrete or ceramic into log-shaped molds. These fire-resistant "logs" are then painted to look like real wood. Note that gas logs are different from consumable fake logs designed to burn in a non-gas fireplace. The consumable fake logs are made from material like compressed sawdust or coffee grounds and substitute for wood.
Hot molten metal gas log production
Why Consider Gas Logs?
The main advantage of gas logs is their convenience and heat efficiency. The whole idea of no ashes to clean or wood to cut is quite appealing! And the designs are more and more realistic, making even diehard wood-burning fans take a second look.
Real wood fireplaces are charming, sure. But they're not always practical. Perhaps you want a fireplace in a room that doesn't have a chimney. Or maybe you're hoping for a fireplace that will function as a reliable and efficient heat source. Maybe you're just tired of gathering wood and cleaning ashes. Gas logs are the perfect solution for someone who wants a blazing fireplace without the downsides.
It's also a safer option. Wood-burning fireplaces tend to be a little less predictable and have fewer built-in safety checks. Gas fireplaces offer more control over the flame height and can't send sparks or embers flying into the room. Most gas models are also equipped with several sensors and safety shut-offs that keep the gas from escaping or the fire from getting out of control.
Breck peninsula ventless gas firebox
Once you switch to gas, you can choose from a wide array of log styles in different colors, styles, and sizes. The logs themselves become a sort of accessory, allowing you to add extra personality and style to your fireplace.
Leading Brands and Manufacturers
Ready to start the search for gas logs? Here are some tried and true brands to get you started. Whether you're looking for vented or ventless, propane or natural gas, these companies make quality logs sets in an array of styles.
RealFyre - RealFyre has been in the gas fireplace business for more than 65 years. They offer several lovely, realistic log sets in both vented and vent-free. They also have a selection of glass fire media for a more modern look.
Monessen - Monessen is an industry leader in vent-free gas products. Some of their logs sets may be a bit pricier, but they are durable and each is hand-painted with exquisite attention to detail. Monessen also makes a priority in promoting environmentally-friendly practices.
EverWarm - EverWarm offers a quality selection of both vented and vent free gas logs. Their popular oak sets come in several sizes to fit a range of fireplaces.
How Do Gas Logs Compare to Real Wood?
Besides the obvious difference that gas logs are fake and don't degrade, there are several other differences between real wood and gas log fires. (For example, gas logs don't bring along spiders.) Here is a quick glance at the differences:
Gas logs can be reused year after year.
Gas logs don't burn down and shift or roll in the fireplace.
Gas logs don't smoke like real wood logs.
Unlike real wood, gas logs "ignite" immediately into full flame.
How to Measure for Gas Logs
Measuring and selecting the right size logs is crucial. Overly large logs will negatively impact the function of the fireplace, while logs that are too small will look strange. Remember that you also have to leave room for the burner and ignition components. Here are some basic guidelines. (You can also use our gas log calculator.)
Start by taking measurements of the inside of your fireplace. (Note that you should round down to the nearest whole number. It also helps to clear out any old logs or grates to have space to measure.)
Measure the width of the front fireplace opening.
Measure the width at the very back of the fireplace.
Measure the depth from the back to the front.
Watch the video below for a demonstration:
Now that you have the basic measurements, you have a general idea of what logs will fit. However, each log set is different and you should check the specific space requirements before purchasing.
Different ignition types also affect the size of logs your fireplace will accommodate.
Manual gas valve ignition doesn't include a pilot kit. As a general rule, you only need 2 inches of clearance between the burner and the side of the fireplace. Subtract 4 inches from the front width measurement and you'll have the length of logs your fireplace will fit.
Safety pilot ignition systems require some space for the pilot light. In general, subtract 8 inches from the front width measurement to find the length of logs that will fit.
Millivolt pilot ignition or intermittent pilot ignition includes hardware for remote control. This means you'll need about 6 inches of clearance on either side. Subtract 12 inches from the front width measurement to find the optimal log size for your unit.
How Do Gas Logs Work?
The purpose of gas logs is mainly for decoration, although their arrangement does affect airflow. In a gas fireplace, the gas (either liquid propane or natural gas) is connected to a burner that has ports for the gas to flow through. The gas is lit by an ignition system, causing flames to spring up around the logs.
There are three main types of ignition systems for gas log fireplaces:
Manual On/Off Valve
This ignition system works by turning on the gas valve and lighting the stream of gas by hand. The flame height can then be adjusted by turning the valve supply up or down. This system is simple and inexpensive, but it is also more dangerous since the gas could be accidentally left on. Note that manual valves are not allowed for liquid propane or ventless fireplaces.
Manual Safety Pilot Valve
The pilot light on these systems is a tiny flame that continues burning even when the unit is not in use. The flame is fed by a tiny stream of gas and is ready to light the rest of the burner ports whenever the main gas valve is turned on. This method is an added safety feature because the pilot prevents gas from leaking into the home unnoticed. It will ignite and burn any gas coming from the burner ports. It also makes it easy to ignite the main flames with the push of a button or switch. In the offseason, the gas can be shut off completely and the pilot light extinguished.
Millivolt (Remote Ready) Pilot Valve
These systems are similar to the manual pilot valves, but they have the option of incorporating a remote control. The downside is that the systems tend to be more expensive and take up more space in the firebox.
No matter which ignition system you use, the basic function of the fireplace is the same. The valve controls the gas flow and the burner directs the gas through ports. The gas is lit by a pilot light or handheld lighter and creates flames.
How To Install Gas Logs
If you're installing a new gas fireplace, you'll need to have a gas line professionally installed. Turn the gas valve completely off before you start the installation. If you're replacing a gas log set, remove the old logs and disconnect the burner from the gas line. Hook up the new burner and arrange the logs according to the instructions.
Framing and installing a built-in ventless gas fireplace
If your burner comes with electrical components for remote control, you can connect these before arranging the logs. The burner often attaches to the bottom of the fireplace with screws. Your model should come with specific information on how to attach it.
Gas logs often come with a metal grate that sits over the burner and contains the logs. Ventless logs must be arranged in a specific pattern so that the flames won't touch the logs. Usually, there are pegs in the grate that the logs slide on to. The instructions will come with explanations or diagrams to show you how to arrange the logs.
Vented logs don't require a specific arrangement. Just keep in mind that you want to leave room for some airflow and not block the burner ports. Wear gloves when arranging the logs since fiberglass can cause skin irritation.
For a gas fireplace without a pilot light, turn on the gas valve and light the gas using a long-stemmed lighter. Follow the proper safety precautions to avoid releasing too much gas or getting burned. If your unit comes with a pilot light it will need to be lit before the first use.
Lit gas pilot
Some pilot lights are lit by pushing an ignition button on the control panel of the fireplace. Other models require you to light the pilot with a match. In any case, read the instructions for your specific model to know exactly how to light the pilot. Once the pilot stays lit on its own, you can turn the knob on the fireplace from "pilot" mode to "on" and ignite the main burner flames.
The pilot light should stay lit throughout the burn season. Once the pilot is lit, you can turn the main flames on and off with a button to operate the fireplace.
If you don't have a safety pilot light, it's important to light the gas immediately after you open the gas valve. If it fails to ignite, turn off the valve and wait several minutes for the gas to dissipate before trying again. If it still does not light after several attempts, turn off the valve and call the manufacturer for help troubleshooting the problem.
How to Clean Gas Logs
Gas logs are delightfully low maintenance, but they still need some cleaning from time to time. Each set is different, so follow the guidelines given by the manufacturer. To clean, shut off the pilot light and allow the logs to cool completely. You can use compressed air, a soft brush, or a vacuum to remove dust and soot.
Woman with yellow rubber gloves holding a cleaning cloth
Sometimes it's helpful to remove the logs to clean them. If you have ventless logs, make sure you know the exact arrangement of the logs before you take them apart. You can even snap a photo if you don't have the manual handy. Putting them back in the wrong orientation can void the warranty.
Use gloves to handle the logs and place them gently on top of some newspaper. Don't use water or any cleaner unless the manual specifically says to. Instead, use a dry rag, vacuum, or soft brush. Be careful to not scratch or chip the paint on the logs.
Most gas logs and burner sets will ship via small parcel post. Log sets over 36 inches can easily weigh over 100 pounds and will be shipped on a pallet to protect them from breaking. The pallets will ship via freight.
For vent-free gas log sets, the burner and gas valve are factory assembled and shipped in one package. Vented gas logs that are non-ANSI certified are usually not factory assembled. In that case, the burner and gas valve will arrive in separate packages.
Always check any shipment for damaged or missing pieces. Contact the manufacturer immediately and do not sign off on any delivery if you notice the damage.
Kingsman Zero Clearance Vent Free Gas Fireplace
It's no wonder gas logs have become so popular. They let you add ambiance and warmth without the extra commitment of maintaining a wood-burning fireplace. Start by deciding whether you want to go with vent-free or vented logs. Then you can measure your fireplace and start browsing through all of the beautiful log options!
And as always, our NFI Technicians are here to help if you have any questions!
With proper installation and annual cleaning/maintenance, this should not be an issue with any log and burner configuration that includes solid refractory logs over porous ceramic fiber logs that are impossible to clean and will hold a smell. Ceramic fiber logs will also break down over time and will require replacement. That being said, you should not be smelling gas with any properly installed ventless gas hearth system unless the fuel supply itself is "dirty." Ventless systems are designed to provide a complete burn and the only byproducts of this process are water vapor and carbon dioxide. If you are smell gas, I would discontinue use of the log set and immediately check for leaks. I would also highly recommend investing in a carbon monoxide detector.
To determine the appropriate size log set for your fireplace, we will need to know the following measurements: front width at fireplace opening, height at fireplace opening, depth (front to back) and rear width.
Submitted by:Tyler M. - NFI Master Hearth Professional on October 25, 2021
Can I use a smaller tank (like a 20 or 40#) for my 34,000 BTU log set? I have a 5' run from tank to log set. This will just be a supplemental heat source, will never run for more than 3-4 hours at a time
Yes, you will just need to have the tank filled more often.
Why can't the vented 24" RH Peterson coastal driftwood be used with a ventless burner?
Decorative logs designed for vented burners do not require placement atop the grate and burner to be as exact as placement of decorative logs atop a ventless burner assembly since the risk of incomplete combustion and the release of carbon monoxide isn't as severe with an open flue. Placement of decorative logs atop a ventless burner results in a flame that burns freely without impinging the logs whatsoever since incomplete combustion resulting from flame impingement would release carbon monoxide into the home.
Can I use vented logs in a ventless fireplace and just buy the burner?
Since the decorative logs designed for use with ventless burners are designed to allow the flame to flow freely and provide near complete combustion, you should never use a decorative log set designed for a vented burner with a ventless burner as this would create carbon monoxide.
My chimney was damage, and after installing a new roof the roofer suggested that I just block the opening when putting the new roof and install ventless gas logs. I already have the gas line there. Do you see any problems with me installing the ventless gas logs?
Because ventless gas log sets actually require a fully-functional chimney, a much better option would be to install a ventless gas fireplace insert into your existing fireplace.
If you are referring to refractory logs vs. ceramic fiber, we have many options to choose from. I recommend browsing through our selection of Real Fyre ventless gas log sets as all Real Fyre decorative logs are refractory and carry a lifetime warranty.
What is the difference between refractory log sets and ceramic fiber log sets?
Refractory logs are superior to ceramic fiber logs as they do not break down over time unlike ceramic fiber logs. Secondly, ceramic fiber logs are much more fragile making cleaning and maintenance a delicate process. Refractory logs will continue to hold and radiate heat for some time after the burner has been extinguished similar to the side of a brick wall which has been exposed to the sun for the majority of the afternoon.
Can all of your ventless propane log sets be controlled electronically with the necessary adapter?
Only our remote-ready units can be controlled electronically. This would include both the variable flame sets and the on/off variety. The units listed as "Safety Pilot" can only be controlled manually at the log set.
What would cause fumes to come off of a ventless log natural gas fireplace?
Most vent free gas log sets will release an initial burn off odor during the first 3 to 4 hours of operation. However, if the set continues to release a noticeable smell when operating, there is likely an issue with log placement. The log placement instructions should be reviewed and a visible check made to ensure that flames are not hitting any of the logs directly. It is also important to service a vent free set on a yearly basis. Accumulation of dust, lint, or pet dander into the assembly can partially clog the air intake, releasing an odor.
Submitted by:eFireplaceStore on January 7, 2015
Most Helpful Answer
from Nocona, Texas asked:
December 9, 2013
Can we have ventless logs in a traditional fireplace that has a flue that can be opened or will it require us to have a log set that requires venting?
This is actually a good question and one that comes up often. If the chimney does have a working damper and is in good shape, you have the choice of using a vented or vent free set. The damper can be closed down most of the way with a vent free set, allowing the heat to circulate in the room for greater efficiency. In the event that you would like to operate the set, without incurring the extra heat, the damper could be fully opened.
Submitted by:Collin C. - NFI Master Hearth Professional on December 10, 2013
Do the pilots stay lit on all of your ventless log sets?
Most of our ventless leg sets do indeed feature a standing pilot light. However, the sets that feature the Electronic Pilot Kit do not; these use a battery-operated ignition system that eliminates the standing pilot. You can use the search options on the left-hand side of this page to select "Electronic Remote Pilot" from the "Pilot Type" menu to see these log sets.
Submitted by:Tyler M. - NFI Certified Specialist on November 15, 2013