B-vent gas fireplaces or natural vent fireplaces use air from inside your home to fuel combustion and rely on the buoyancy of hot gases to vent exhaust through dedicated pipe systems. This simple design makes them cheaper and easier to install than direct vent models, but they are much less efficient. You'll want to carefully consider your budget and heating needs before deciding whether a b-vent fireplace is right for you.
What is the difference between direct vent and B-vent fireplaces?
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.
we are looking for a b-vent fireplace insert....but we don't want gas logs...instead we want one that has the crushed glass in the bottom and flames come up thru the crushed glass...do you offer a unit like this?
B-vent fireplaces have largely waned in popularity as they do not provide any efficient or measurable heat, so the options will be limited and there is no model offered that will be configured with glass. You will have many more options when searching for a direct vent or ventless system configured with a fire glass burner.
I have a B Vent fireplace that doesn't work and I would like to put in a ventless unit. My Be Vent chimney is in a non masonry chimney that runs two stories up. Do I have to worry about a ventless unit being to close to the flammable walls? Can it go into the B Vent fireplace insert hole? What do I do with the B Vent stack?
As long as the vent free fireplace is installed into a framed opening that meets the size requirements, there will not be an issue with too much heat transfer. The vent free unit can indeed be installed in the spot previously occupied by the B vent unit. You may have to reframe to accommodate the new model, as the sizing is unlikely to be identical. The B vent stack can be left in place if you wish. I recommend removing a section of it so that it will not be resting directly upon the new unit. A 2 x 4 can be framed under the stack to support it.