While similar in basic design principles, there are several differences between these two appliances. A B-vent appliance uses what is known as type B gas vent. This is a single tube that vents exhaust gases to the atmosphere and is always run vertically through the roof of a home. In order for the unit to operate, combustion air is drawn through the open front of the unit. In this sense, a B-vent appliance is much like a traditional wood burning fireplace. The two types also share the common design aspect of being relatively inefficient and they are primarily intended for ambiance. One advantage to a B-vent appliance however is that they are generally cheaper than direct vent units. Direct vent appliances use a sealed pane of glass to cover the fireplace opening, relying on a co-axial rigid vent pipe to both vent exhaust gases and draw combustion air for the burner assembly. They are more efficient than any other type of vented gas fireplace and as such, they can serve as an excellent supplemental heat source. Venting these units is relatively easy, as the vent systems can be routed both vertically and horizontally. One common drawback to direct vent models is the reflection of the glass, which can be a visual detractor. However, almost all customers grow accustomed to the look and no longer notice it.
on July 13, 2017