Do Gas Fireplaces Have A Flue?

The passageway in a chimney through which combustion fumes are moved to the outdoors is known as the “flue,” and your gas fireplace may or may not have one. Several chimney ventilation options are available for gas fireplaces. The flues in some operate very differently from traditional masonry chimneys and with others, no venting is needed at all. These three types of gas fireplaces are natural vent gas fireplaces aka B vent gas fireplaces, direct-vent gas fireplaces, and vent-free. It is typical for U.S. communities to establish mandatory rules regarding the professional installation of a gas fireplace and, as applicable, the chimney flue.

Natural Vent (B Vent) Gas Fireplaces

A flue is used for natural vent gas fireplaces, which often utilize existing factory-built metal chimneys or masonry chimneys. The air within the home feeds gas fireplace combustion, and the warm air is drawn out of the home through a flexible liner or a single pipe in the chimney.

With some types of natural vent fireplaces, an essential element of the installation is to ensure that the flue is the correct size for the appliance, per the manufacturer’s instructions.

Direct-Vent Gas Fireplaces

No chimney is required for direct-vent gas fireplaces. The “flue” used in these heating appliances is in the form of a co-linear venting system that is usually vented directly outside through the nearest wall or the ceiling and roof. This venting system is highly efficient in that it eliminates the heat loss characteristic of conventional chimneys. A direct-vent unit requires a sealed glass door installed, which serves the following:

• Maintain proper combustion
• Ensure good indoor air quality
• Ensure appliance efficiency

Ventless Technology

No external ventilation is used for vent-free gas fireplaces. Much controversy has surrounded ventless fireplace appliances. On a wide scale, U.S. jurisdictions have outlawed the use of this technology, though most concerns have been addressed in new modern ventless gas fireplace designs. A manufacturing expert has stated that the technology used in vent-free gas fireplaces is of the catalytic-converter type not much different from exhaust systems used in many new cars. The technology cleans hot air as it is exiting the combustion chamber.

Air from inside the home is used to feed fires in vent-free gas fireplaces. The combustion by-products released into the home are primarily water vapor and carbon dioxide. The water vapors can cause increased levels of humidity in the home, which increases the risk of mold growth. It is not harmful to inhale low concentrations of carbon dioxide, according to experts.

Vented Vs Ventless Gas Fireplaces

Gas fireplaces continue to grow in popularity. If you are trying to decide whether to get a vented gas fireplace or one that is ventless, consider the following:

Pros of Vented Gas Fireplaces

• Vented gas fireplaces provide greater safety because indoor air quality is not affected.
• The flames have a more realistic appearance if you have a direct-vent or B-vent gas fireplace.
• Venting can be installed horizontally through an exterior wall.
• No heat loss.

Pros of Ventless Gas Fireplaces

• More affordable.
• Easy installation
• Efficient heat that provides warmth more fully and rapidly

Contact Guardian Chimney Sweeps

The CSIA-certified chimney technicians at Guardian Chimney Sweeps are happy to answer questions about ventless gas fireplaces and those with flue systems. Call one of our numbers below for installation services or for chimney inspections, chimney cleaning, masonry rebuilds, and all your chimney-related needs.

Conroe – (936) 271-9781

Houston and surrounding area – (713) 401-2011

Toll-free – (888) 306-6069