Vented vs. Non-Vented Gas Logs: Which Type is Right for Your Home?
- Published onMay 30, 2024
- Appliance Maintenance and Care, Resources
Choosing between vented and non-vented gas logs mostly comes down to personal preference. Vented logs offer a realistic wood-burning look but are less efficient for heating. Non-vented logs provide better heat output and don’t require a chimney, but they might not look as natural.
When you search for gas logs to install in your home, you’ll find two different types: vented and non-vented (or ventless).
Both offer a mess-free alternative to traditional wood-burning fireplaces, but they look, feel, and operate differently from one another.
Without understanding these differences, you risk spending money on a set that probably can’t be returned, leaving you frustrated and unsatisfied.
So, to help take the guesswork out of choosing which type to install, we’ll cover everything you need to know about both.
Comparing Vented vs. Ventless Gas Logs
When deciding between vented vs. non-vented gas logs, the best choice for you and your home will ultimately depend on five things:
- How you want the gas logs to look
- If you want the logs to produce heat
- Your current fireplace design
- How much space you have in the room you plan to use them in
- The cost for the logs and installation
Once you take these into account, choosing between the two will be easy.
Let’s go over each of these key factors so you know what you’re getting and what requirements come with both sets of gas logs.
Appearance and Burner Design
If you’re looking for a set of gas logs that closely resembles a real wood-burning fire, then you should be looking at vented gas logs.
While both vented and non-vented log sets are designed with realistic bark textures, wood grain details, and even char marks, vented sets have a more authentic look because of the way their burner is designed, how they burn the gas, and how the logs are stacked.
Vented Logs
On a vented set of logs, the gas burner sits under the logs. The burner tube is covered with silica sand to disperse the gas evenly across the burner tray and vermiculite to recreate the look of burning embers.
Together, they produce large, vibrant yellow-orangish flames with natural flame patterns that engulf the logs from underneath. The logs are stacked in tiers like a real fire, and in most cases, you’ll have some wiggle room to customize where the smaller logs are placed on top.
Non-Vented Logs
The gas burner assembly on ventless sets is designed specifically so the resulting flames don’t touch any of the gas logs. This is done through a burner tube or gas ports on the burner itself.
This means the flames won’t always start from underneath the logs and instead weave around them or start in front of them.
For gas logs to be considered “ventless”, the gas must burn completely so no byproducts are released back into a home. With this complete combustion, you’ll notice the flames on a non-vented set of gas logs are cleaner and have a bit of blue in them.
They’ll also be smaller and less natural-looking than vented logs, and you won’t be able to change the log positions because doing so would create soot or carbon monoxide.
Most non-vented gas logs today also use vermiculite to mimic the look of embers burning in front of or between the logs, but vented logs are still the better option for a more natural flame and authentic wood-burning look.
Heating Efficiency
Where non-vented gas logs lack in comparison to the realistic appearance of vented gas logs, they more than makeup for it in how well they can heat a space.
Vented Logs
Vented gas logs are labeled as such because they burn incompletely without efficient air-to-fuel ratios. This incomplete combustion produces byproducts that need to be vented outdoors and is the main reason why their flames have a yellow-orangish color to them.
They can be vented using an existing chimney flue or by directly venting them out the side of a home.
If you have a chimney and want to install vented logs, the damper—which controls the airflow inside your firebox—must be fully opened and secured with a damper clamp to prevent it from closing. This guarantees the combustion gases have a place to escape and can’t be released back into your home.
Because they have to be vented, most, if not all, of the heat generated from the flames on a vented set of logs will be lost up the chimney or out the vent with the combustion gases.
Non-Vented Logs
Non-vented gas logs burn cleaner and more completely than vented logs. With precise control over the air-to-fuel ratio, they operate without releasing any byproducts into a home, eliminating the need for venting.
You can leave your damper slightly cracked so most of the heat from the flames is pushed back into your home instead of out, providing warmth year-round.
This heat is especially nice to have if you ever lose power or can be used to help heat your home, saving you money on your heating bill.
Space Requirements, Venting, and Clearances
Most brands make their vented and non-vented log sets in different sizes so you can choose the correct size based on the dimensions of your firebox.
To determine what size logs can be installed in your firebox, there are four measurements you’ll need to take:
- Measure the width across the front opening of your firebox.
- Measure the width across the back wall of your firebox where it meets the corners.
- Measure the depth from the front opening to the back wall of the firebox.
- Measure the height from the floor of the firebox to the top opening.
Each log brand provides the minimum dimensions required based on the burner and log size. Always check these dimensions before buying so you know they’ll fit in your fireplace.
Vented Gas Logs
Vented gas logs can be used in masonry-built fireplaces or in existing manufactured fireplaces that already have a vent system installed.
Since vented gas logs require the damper to be open when they operate, you’ll need to make sure the opening is large enough for the specific set of logs you want to install.
This minimum opening requirement is determined by the type of fireplace you’re using (masonry or manufactured), the height of your chimney or venting system, and the BTU rating of the gas logs. This requirement varies by brand but should be detailed in the manual.
If you plan on installing a new direct-vent gas log insert, it will have its own venting system to expel the combustion gases outside. Before choosing one, pay attention to the vent termination clearances.
In most cases, these venting systems can be installed vertically or horizontally, but there are specific clearances for each termination method. This includes minimum distances from windows or any openings back into the home, outside and inside corners, or how high they need to terminate above roof lines.
If you plan on installing a vented set of logs outdoors, there will likely be clearance from any combustible material above them, like an overhang.
Non-Vented Gas Logs
The space requirements and clearances for non-vented logs are stricter because of the amount of heat they produce and the fact that they do not require venting. To determine if you can install vent-free logs in your home, you’ll need to take a few additional measurements:
- The distance from the side openings of your firebox to a wall made of combustible material (note: drywall is not considered combustible).
- The distance from the top of your firebox opening to your ceiling.
- If you have a mantle, measure how high it sits above the top of your firebox opening and its depth. Each brand has its own clearance requirements to mantles, so you’ll have to check each manual to make sure what you have meets the clearances for the set you’re looking at.
Additionally, you’ll need to calculate the amount of fresh air (combustion air) in the room where you plan to use them.
A gas appliance that doesn’t receive enough fresh air can lead to incomplete combustion, which produces carbon monoxide.
To calculate combustion air in a room, use this step by step guide:
If the room where you intend to install the vented gas logs is considered a confined space, you’ll need to add fresh air into the room by following one of the procedures mentioned in section 304 of the National Fuel Gas Code.
The Cost of Gas Logs and How Much to Have Them Installed
The cost difference between vented and non-vented logs has narrowed over the past five years. This decrease in price gap can be attributed to non-vented logs being designed to have a more realistic look and the increasing popularity of gas fireplaces among homeowners in general.
And when homeowners want more of something, new construction homebuilders will make sure it’s included in their homes as well. This increase in demand only drives prices further up to new price points.
However, the cost of gas logs ultimately depends on the brand, the quality of the logs, and the features of the set.
Once you start comparing gas log sets that go in an existing firebox and entire gas log inserts, you’ll see a significant change in price. Not only are gas log inserts more expensive, but they’ll also cost even more to install.
To help give you a better idea of the cost differences between each type, take a look at the table below:
Average Cost of Gas Log Sets and Gas Log Inserts
| Gas Log Type | Cost | |
|---|---|---|
Vented Gas Logs |
$1,030 | |
Non-Vented Gas Logs |
$905 | |
Vented Gas Log Inserts |
$2,104 | |
Non-Vented Gas Log Inserts |
$1,721 | |
Though these prices may seem high, they represent the average cost of the ten most popular log sets for each type.
There are plenty of budget-friendly gas logs available in the $100 to $300 price range. However, the average cost for gas log inserts shown in the table is going to be the standard.
Installation Costs for Gas Log Sets
You won’t see much of a price difference when comparing the installation costs of vented vs. non-vented gas logs since both types can only be installed in an existing firebox, and both types are installed the same way.
Regardless of which type of gas log set you choose, you’ll need to get a chimney sweep done before they’re installed. A chimney sweep involves hiring a licensed technician to inspect your chimney for any openings, soot buildup, or creosote (a dangerous byproduct of burning wood) and cleaning the flue, firebox, and damper.
The real difference in installation costs will depend on whether you already have a gas line installed in your firebox or not. If not, you’ll need to pay for a licensed contractor to come in and properly install one.
This additional expense will vary based on where you live and your local contractor’s rates. To give you an idea, you can typically expect to pay around $5 per foot for the gas piping and then labor and other materials on top of that.
Installing Cost for Gas Log Inserts
If you decide to have a vented or non-vented gas log insert installed, the installation costs will only increase because they’re more complicated and take longer to install, with each part of the installation having to be done in steps.
Once a gas log insert is set, there’s no access behind it, so the gas piping needs to be inspected beforehand. Once this inspection is done, another inspection is required to check the connection (and vent connection if installing a vented gas log insert) before the contractor can come back and light it.
At a minimum, these can take 4 to 6 hours to install, and the entire process can take up to three days with inspections. Meanwhile, installing gas logs in an existing firebox should only take two hours and two days to complete with inspections.
Making Your Final Decision
As you can see, the choice of vented vs. non-vented gas logs for your home comes down to meeting the necessary clearance and space requirements and what you value most.
Are you someone who wants the more traditional wood-burning look vented logs offer, or do you want to fill your room with a cozy heating source that non-vented logs can provide?
Let us know if this helped you make your decision and which log set you went with. We’re always interested in hearing from actual users about why these two types of gas logs work well for them.
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