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.
I have a Superior B vented fireplace, model GHC/GRD-5500 series with a fan. We just bought this condo about 8 months ago. I have tried to use it but it is almost useless as far as any heat goes. It is just a waste of propane gas. I suspect that this unit is mostly for looks. Am I right? The unit was installed new when the condo was built, which was in 2003. What can you tell me?
By Tyler M. - NFI Certified Specialist on December 5, 2013
Our B vent heat vent began to smoke this evening, a steady stream of steam that began to thicken, ended as soon as we doused the fire which had been burning well for 4 hours and had recently been given the thumbs up from a chimney sweep/ handyman. There was no smoke above normal coming from the fire in the grill. Is it possible something fell into the venting portion that is separate from the fireplace. Our model is built into the chimney stack with the vents enclosed separately to the side, directly under the chimney.
By Kevin E. - Fireplace Specialist on January 29, 2013
Indeed, it is possible that there is some sort of foreign material in the vent system that is beginning to burn and in turn smoke. However, I apologize but I don't quite understand the venting system described. Is there a masonry chimney that is adjacent to the fireplace but not used for venting the B vent fireplace? We are happy to offer any insight we can.
By Nick from Houston on September 30, 2013
Do the B-Vent fireplaces have to have a glass front to operate? Do you have one that is open in the front, like an old wood fireplace, and that uses a 6 inch vent?
By Tyler M. - NFI Certified Specialist on September 30, 2013
No, B-Vent fireplaces do not have a solid glass front like direct vent models. They are designed to be burned open to the room, but most units do have optional bi-fold glass doors. Yes, we have several B-Vent fireplaces that have a 6" inner diameter flue collar. Please see a couple such models here:
Can a B-vent fireplace be vented into an existing brick chimney?
By Tyler M. - Fireplace Specialist on December 13, 2012
A B-Vent fireplace can indeed run its Type B pipe up an existing brick chimney. You can run the Type B pipe into a masonry wall, then pass through it with a thimble and connect it to a flexible aluminum liner.
By John from New York on December 20, 2013
Which 36" B-vent natural gas fireplace has the most realistic looking logs?
By Collin C. - NFI Master Hearth Professional on December 20, 2013
I would like to put an Empire Keystone 36" LP gas fireplace in a corner of my lower level. There is an unused block chimney behind the wall in the corner. I would like to use a corner mantel. Is there a way of doing this, or is there an Empire unit that would work without building a chase or fake wall to hide the b-vent? I read that you have to go up 2' before putting in a 90 degree elbow. I would like to go right into the chimney and use a liner kit to go up and out the roof. Is there a way of doing that?
By Collin C. - NFI Master Hearth Professional on November 4, 2013
Every B-vent fireplace will require a limited vertical run of pipe before being directed horizontally. This is to prevent the unit from spilling combustion gases back into the room, due to limited drafting.
The only type of unit that could be vented directly rearward is a direct vent fireplace. This type of unit could have its vent system directed immediately into the chimney and then converted into a co-linear vent tubing system. The system will use a pair of 3 inch aluminum liners that would run up the chimney flue and terminate to a special adapter. If this is a setup you wish to consider, I can work with you to determine all the necessary components to complete the installation.
By Kevin from Vancouver, BC on May 14, 2014
I want to build a recess box for a TV above my 4" b-vented gas fireplace. There is plenty of room in the insulated chimney cavity but the venting pipe is a little closer to the wall than I'd like. how much distance should I keep the framing/box away from the pipe?
By Collin C. - NFI Master Hearth Professional on May 14, 2014
B vent piping should maintain 1 inch of clearance to combustibles at all times. As long as this minimum clearance is met, combustibles are not in danger of charring over time.
By Bill from Seattle, WA on February 18, 2015
We had a pellet stove that vented through a 4" stainless steel flex pipe. it exited out the top of our chimney. Can we use the same 4" pipe for a natural gas insert?
By eFireplaceStore on February 18, 2015
The liner could be adapted to a B-vent natural gas insert and potentially to a direct vent model as well, but another 3 inch liner would need to be installed for combustion air purposes.
By David from Lewisburg, West Virginia on December 3, 2013
We have a wood burning fireplace in one room and have added on a bedroom on the opposite side of the living room. We want to cut into the existing chimney which has a 12" flue, and would like to run two 4" vent pipes through the 12" flue and have two b-vent units - one in the living room and one in the new bedroom. Is 4" sufficient for each unit, and what is the maximum BTU available in the b-vent units?
By Collin C. - NFI Master Hearth Professional on December 3, 2013
I have a Devonshire direct vent gas fireplace. Can I run this as a B-vent?
By Tyler M. - Fireplace Specialist on December 18, 2012
No. For proper venting, you must use the direct vent pipe (coaxial, pipe-within-a-pipe) specified in your owner's manual.
By Mills from Texas on December 26, 2013
My gas log comes on sometimes, burns for about 15 minutes, then clicks off. I wanted to replace it with a pan burner with the fire glass and was told that I couldn't do that because I have a B vent fireplace. I'm not quite understanding why that would matter. Can you tell me?
By Chris on December 26, 2013
Unfortunately, B Vent fireplaces are only tested and listed to be used with the log set and burner that is included with the fireplace. Vented log sets simply produce too high of a BTU output for the fireplace and vent pipe to handle.
By Tom from MI on December 30, 2014
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?
By eFireplaceStore on December 31, 2014
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.
By Dixie from North Carolina on October 5, 2013
Years ago, we removed a wood burning stove from our house. A brick wall is left with the hole from the wood stove where the pipe from the stove goes to a brick chimney. What would be our best option for a gas fireplace? Should we use a vent free, or B vent fireplace?
By Collin C. - NFI Master Hearth Professional on October 7, 2013
Either system could be used in your case. The B-vent fireplace could be utilized, but the vent pipe will need to be routed up and through the wall thimble, with a flexible liner run up the brick chimney. Please keep in mind that B-vent fireplaces are largely for appearance purposes and provide little supplemental heat.
A vent free fireplace has a lower flame, but offers a great deal of supplemental heat. You would not have to utilize the chimney. Vent free units are best used in larger rooms with opening to adjacent rooms for combustion air. Either a B-vent or vent free unit could be framed into a combustible enclosure directly in front of the fireplace.
By Bev from Sumas, WA on April 15, 2013
I am looking for a B-Vent fireplace to replace an older unit. The venting I have is 5 5/8". Will this work with a unit that is 4 inch ?
By Chris on April 15, 2013
I would suggest against using a larger or small pipe than what the manufacturer has recommended.
By Ronald from Stanwood, WA on March 28, 2013
I have a Heat & Glo b-vented gas fireplace installed with a 6.5 exhaust vent and I'm looking for a new unit. Do you have anything that would work with my existing venting? What would I need to do to make a new unit work?
By Tyler M. - NFI Certified Specialist on March 28, 2013
B-Vent fireplaces are waning in popularity, so it is becoming more and more difficult to find new models. We do offer some models that have a 6" diameter B-Vent outlet, but none with the 6.5" that you mentioned. While it would be feasible to do a 6" to 6.5" increase to tie the unit into your existing pipe, we do not offer such a piece. You would need to have something fabricated to serve as the increaser. To see an example of a 6" B-Vent model, please see below:
We want to put a gas fireplace into the first floor family room of our existing two story house. We like having no glass in front of the fireplace. Is there a way to go up with a B vent inside and then go out through an outside wall diagonally/horizontally so it doesn't have to go through the second story, or will we have to go with a Direct vent?
By Collin C. - NFI Master Hearth Professional on December 5, 2013
Unfortunately, a B-vent fireplace must terminate vertically. Your options would be to run the vent through the second story and roof or the vent could be directed horizontally to the outside wall, then vertical along the side of the house in a chase. Direct vent fireplaces are the only variety that will allow a horizontal termination.
By Kevin from Webster, NY on September 10, 2013
Do you have direct vent fireplace units that fit a rough opening of 45 1/2 inches wide?
By Collin C. - NFI Master Hearth Professional on September 10, 2013