Vented Gas Logs

Vented gas logs in contemporary styles, as well as traditional styles.

About Vented Log Sets

The vast majority of gas log sets are made from ceramic-bonded refractory cement. This allows the logs to be molded from casts of real logs to give them a highly realistic appearance while making them resistant to even the most intense gas fires. Additionally, there are a few sets that are sculpted from ceramic fiber. These log sets are just as fireproof as the cement logs but reflect more heat back into the room while being more lightweight... And also not as durable as cement, so handle with care!

A typical small set (20" to 24" wide) of refractory cement logs is around 50 pounds, and that's not even counting the burner! Some of the larger sets can get up to 500 pounds in weight, although individual logs rarely weigh more than 15 pounds.

These gas log sets are sized approximately according to the width of the log stacks. That means if you see a 24" log set, it is no more than 24" in width when match-lit. Burner pans, valve kits, Millivolt switches and other add-ons can add even more width to the set. If (for example) you have a 24" wide fireplace (aside from the fact that you have a tiny fireplace) it is not recommended that you get a 24" log stack but a shorter one so that you have natural space on either side.

Height varies from size to size, and the type of burner you choose. All of these log stacks are designed to fit in a standard, up-to-code fireplace. The difference is that some have low profiles which could leave a large gap in a high fireplace, and tall stacks that will fit in a standard fireplace but might look too cramped. A valve vanisher added to the ignition system adds at least 2" more to the height, so if you're considering one be aware that it will make the stack taller.

Types of Gas Log Sets and Uses

A single face gas log set is designed for use in a standard fireplace with one opening. The logs stack on the burner in such a way that the hardware is covered up when viewed from the front

A double face gas log set is usually used in a see-through (double-sided) fireplace that has two viewing openings, and sometimes even a peninsula (three-sided) fireplace. The burner is designed to be viewed from multiple angles, and the logs stack to cover the hardware from either view.

Most gas log sets have logs that have one finish (bark or "split" bark-less wood) on the logs that give it a specific appearance. A certain few log sets are reversible, which means that the logs (and the large front log in particular) have a different finish on either side (usually bark on one, split on the other) that allows you to choose what you see. If (for example) you buy a reversible double-face gas log set, you can have bark on one side of the fireplace while displaying split wood on the other.


We do NOT recommend that you try to install gas logs on your own because they are complicated appliances that may require modification to your home. To ensure that they are installed correctly, it is best to hire a certified professional installer. This will protect your safety, along with making sure that the gas appliance matches local fire codes and insurance liabilities. 

Proper Set-Up


Improper Log Set-Up

A log set installed in a fireplace of the same width will look cramped and won't leave enough room for standard valve and ignition systems.


Proper Log Set-up

Using a slightly smaller log set will look more natural and leave room for add-on components.

What is a valve vanisher for?

Fireplace Valve VanisherSome log sets have the option of an ignition system installed in a valve vanisher. This is a metal plate that installs under the log set burner and houses a valve and/or electronics that would otherwise have to be installed (visibly) on the side of a gas log set.

What is a Millivolt ignition?

Certain gas log sets offer a Millivolt ignition system. This is a super-efficient electronic ignition system that uses a thermocouple to draw electric power from the flame of the pilot light. Because of this, Millivolt systems do not require an external power source and will still work even during a power outage.

What does "ANSI Certified" mean?

Some of the gas burner ignition options in these log sets will say that they are ANSI certified. This means that they meet the Z21.60 standard of quality for decorative gas fire features. Many jurisdictional fire code standards require this standard. Most other products meet the ANSI Z21.84 standard, but if you're not sure what you need speak with your installer and give us a call at 1-888-986-1535 so that we can see what will meet your needs.

Types of Fireplaces

The terms "vented" and "vent-free" refer to whether your fireplace has a chimney or vent.


Vented Fireplace

A vented gas log set requires a fireplace with a working chimney or vent. These act as an exhaust for the fumes from the burning of the gas or propane. Flames from a vented set are usually large, natural, and yellow. Most of these sets come with a damper clamp to keep an chimney damper open when installing in a wood-burning fireplace. You CANNOT install a vented log set in a vent-free fireplace.


Vent-Free Fireplace

A vent-free or ventless gas log set does not need a chimney or vent, but must be installed in an area with adequate airflow and ventilation. Flames from a vent-free set are usually low, hot, and red or blue. Typically you CAN install a vent-free log set in a vented fireplace, but you will need to close the vent or damper.

Most jurisdictions have ordinances in place that prevent vent-free fireplaces from being installed in bedrooms and bathrooms.

Can I use these log sets in my outdoor fireplace?

Some of these log sets can be ordered for outdoor use, but don't assume that they all are outdoor compatible. For example, Rasmussen® brand log sets all have an outdoor option which will swap the sand the burner typically includes with silica granules that are less likely to get clogged up by moisture. Although you can order any Rasmussen log set for outdoor use, if you are planning to use it outdoors you should probably get a burner that is made from weather-resistant stainless steel.

Last updated on January 31st 2018.