What is the difference between ?DIRECT VENT?, ?B-VENT?, and ?VENT-FREE? gas fireplaces?
e are three different terms that represent three different ways of ‘venting’ a gas fireplace, that is, to supply combustion air to the fireplace and evacuate combustion gases out of the house. B-VENT: In Australia, the term ‘open flue’ is commonly used instead of ‘B-vent’. B-vent means a traditional type ‘B’, 4′ (102mm) rigid pipe used to evacuate combustion gases. It can also be a certified flexible aluminium liner of the same diameter, inserted into an existing masonry chimney or a prefab chimney. A ‘B-vent’ (or open flue) gas fireplace draws air from inside the house through ports located on the firebox. Usually, a fresh air source is provided as close as possible to the fireplace to insure a constant supply of oxygen in the room, which is necessary to achieve a good combustion and an adequate draft. A fresh air source will also prevent negative pressure problems that can be caused by air moving equipment, such as a heat exchanger, a bathroom fan, or a range hood. DIRECT VENT: In Au