The gas fireplaces can use one of several different venting systems. One of the options will be the natural vent or the B-vent system. Along with the direct vent and the ventless gas fireplaces there is sure to be one of the systems that will fit your home design and budget.

The B vent or the natural gas fireplace vent uses the air in the room for the combustion process. The air is drawn in from the front of the gas fireplace unit. After the combustion process it is removed from the room by a vent that will terminate above the roof. This is along the same lines as a furnace. This is a bit more decorative but is also less effective direct venting systems. The B vent or the natural venting system is somewhat less expensive then the direct venting system.

The gas fireplaces direct vent system is completely self contained. It does not use or return any of the air from the room. This system draws air from the outside, uses this for combustion and returns the by products to the outside. This system uses a coaxial pipe or a two in one pipe system. The inside or the smaller pipe expels the used air, the outer pipe draws in the fresh air. The fresh air is heated as it is being drawn in around the heated air being released. This makes for a very effective heating system. The pipe can be ran through the wall horizontally or can also be ran vertically through the roof. The glass doors on the front of the unit will remain closed while the gas fireplace is operating. Most of the glass doors can be replaced if needed as these are considered to be gas fireplace accessories like the rugs, fireplace tools and the wood holders.

Then there is the ventless gas fireplaces. This is truly what it refers to. No vent, chimney or flue is needed. The air is drawn in from the front of the unit, used in the combustion process and is returned into the same room. This will of course require the glass doors to be opened while the fireplace is operating. The ventless also known as the freestanding gas fireplace use the most inexpensive of all the venting systems as nothing is needed except the gas line. Not all of the major manufactures will produce the ventless systems. The ones that are produced will have the Oxygen Depletion System, also called the ODS. This system will monitor the oxygen level in that room. If the levels drop by or around 2 percent, the unit will be turned off. While most states do not have a problem with the installation of the ventless gas fireplaces, several of the states may require a permit to install them. It is very limited but few of the states do not allow them at all. Be sure to check states codes in your area.