How To Measure For Gas Logs

Firebox Sizing: How To Measure Your Fireplace For Gas Logs

Where To Measure Your Fireplace


Sizing And Specifications

By simply measuring the back width of your firebox, you can determine what size gas log set you will need. The chart below can be used as a guide to select correct log set size. Log set sizing charts vary somewhat by manufacturer so we've included the chart below that will work with all of our gas log sets.

Sizing Notes:
Note: If you are installing a Safety Pilot Control Kit or Wall Switch Kit we've added 3" to the width of the firebox opening minimum. If you are installing a Remote Control Kit, we've added 6" to the width of the firebox opening minimum.


Log Size

Minimum Rear Width for:
Gas Logs Only 
or With Standard Hearth Kit

Minimum Rear Width for:
Safety Pilot Control Kit
or Wall Switch Kit

Minimum Rear Width for:
Remote Control Kit









































 *Front and Rear widths are provided as a general guide for selecting proper log size.

Gas Requirments
Is a gas line currently installed?

If no, then a gas line or propane will need to be installed upon installation on the logs. A licensed gas installer should install your gas line.

If yes, please verify the following information: Is the natural gas line currently in place for a log lighter? If so, a larger gas line will most likely need to be installed. Again, any licensed gas installer can supply this service.

Vented vs. Vent Free Gas Logs
Gas Logs are sold in vented and vent free or unvented styles. Vented logs require an open damper in the fireplace to allow the heat to flow upwards and out of the chimney. Vented logs mirror the action of a wood-burning fireplace with the damper open.

While the vented logs do produce heat, vent free logs function more like a space heater because they do not require an open damper and the heat is confined to the room. However, vented logs are more aesthetically pleasing and not only supply some heat, but double as room decor.

Vent Free logs require an Oxygen Depletion Sensor (ODS), a device that senses the amount of oxygen in the room and automatically shuts off the log set when oxygen level drops below 18%. The pilot on a vent free set that has been automatically shut off by the ODS can only be re-lit when fresh air is available. This may require opening a window or a door to another room or cracking the damper open slightly.

Gas Log Efficiency Ratings
On average, vented gas logs are 47% efficient (2 times more efficient than wood-burning fireplaces).

On average, vent free gas logs are 99% efficient (4 times more efficient than wood-burning fireplaces).

Fireplace Requirments For Vented Gas Logs
Vented Gas Logs are to be installed only in a fully, vented, noncombustible fireplace with an open damper. The chimney must be free of any obstructions. The fireplace must be designed and approved to burn wood. Like burning natural firewood, your gas log set is designed to burn with yellow, smoky flames. For this reason, it must be adequately vented. The fireplace flue must be at least 8" at its smallest dimension.

Your fireplace must have a gas supply line that has been installed by a qualified technician in accordance with all local codes. The gas supply line must be 1/2" minimum interior diameter. If the gas line to your fireplace is longer than 20', a larger diameter line may be necessary.

Before installation, be sure to clean your fireplace floor of any ashes or other foreign materials. It is recommended that a chimney sweep or other qualified person inspect the fireplace and chimney before having your log set installed.

Fireplace Requirments For Vent Free Gas Logs
Before having vent free gas logs installed in a solid fuel burning fireplace, the chimney, damper and firebox must be thoroughly CLEANED of soot, creosote, ashes, loose paint and inspected by a qualified chimney cleaner. Some older fireplaces may need repair prior to installing this appliance.

Any outside air ducts and/or ash dumps located on the floor or wall of the fireplace must be permanently sealed shut during installation with a heat resistant sealant. Do not seal the chimney flue damper.

Gas Log Valves
The Standard ON/OFF Valve - This valve is controlled manually and the logs will need to be lit each time they are burned.

The Safety Pilot Kit - This valve may be installed with the logs to allow the pilot to burn constantly, which does not require the logs to be lit each time they are burned. It is possible that additional installation costs may be charged for installation of a safety pilot.

Gas Log Accessories
Remote Controls - Allow for the automatic turn on/off of the log set from anywhere in the room. Styles vary from allowing the customer to turn the flame up/down, installation of a wall switch or simply turning the set on/off.

Other Available Accessories include branches, sand, embers, lava granules, pine cones, bonus logs and wood chips to help customize the look of your fireplace.

RADCO certification is the standard for vented logs. The installation, including provisions for combustion and ventilation air, must conform with local codes, or in the absense of local codes, to the latest edition of the Natural Gas Fuel Code (ANSI Z223-1 and NFPAA54). Vent Free or vented logs should be C.S.A. certified to the unvented room heater standards (ANSI Z21.11.2) and as a vented decorative appliance (ANSI Z21.60).

Propane Gas Logs

Gas log sets are designed for use for either Natural Gas or Propane fuels. Sets designed for use with Propane Gas must be installed with a safety pilot system. In most gas log sets, the safety pilot is included. Never use Propane Gas in a log set designed for use with Natural Gas or Natural Gas in a log set designed for use with Propane Gas.