Well, that's the way it used to be done when folks tired of their fireplace and retrofitted with gas logs. There are some concerns about that type installation today with regards to energy efficiency and CO emissions.

I'm guessing most responses will be to avoid this type of set-up.

That being said, I'm using that configuration in my current home. I don't use the logs a lot, primarily to take the "chill off" and opening the damper when I do. I also have a CO alarm in the room to monitor the presence of that.

agree with above post...if looking for heat and BTUs, then vent free is the way to go...

IMO

Are you in California, or some other location with unique code requirements?

I think you have some of the products confused. Vent-free logs put nearly all the heat into the room, and they do not require a flue. AFAIK there is no code requirement to weld a damper shut; you just shut it normally and leave it that way.

We have Real Fyre vent free logs in our masonry fireplace, and I usually leave the damper open a little bit. Our house was built in 1940 and its not that tight, but I just like having a little make-up air from the flue since the fire is burning up oxygen.

There is no requirement to have a flue for vent free, so there was no need to have the flue inspected before they were installed. The oxygen depletion system was part of the log set, and we added a new CO detector in the room. We did need a permit for the gas installation, but that was handled by the plumber.

We bought the logs from Hansen Wholesale, and they don't really recommend vent-free over their vented products. However, we like the way they work and look, and are very satisfied. We have not noticed any odor while they are burning. YMMV.

Bruce

Yes, you can use a ventless gas log set in a wood burning fireplace with the damper closed. They put out a lot of heat as they burn pretty much 100% efficient and all that heat is kept inside the house (not out the chimney). You might want to leave the damper cracked as they vent some odors, carbon dioxide (NOT carbon monoxide) and water vapor into the house otherwise.

Thank you all for your thoughtful replies. I understand that ventless gas logs do not require the damper to be open but I have read some conflicting opinions regarding how safe ventless gas logs are in terms of their byproducts. Additionally, our daughter has asthma and my better half can be a little irrational when it comes to these things.

I suspect this sounds like a strange setup but I am trying to evaluate whether we could use a ventless gas log set with the damper open. We are looking at a ~38,000 BTU model w/ variable remote.

1. Will this setup produce enough heat to create the draw/draft/air-flow up the chimney? Some of you recommended cracking the damper slightly, which I think you are recommending to exhaust some of the odors, CO2, perhaps any tiny residual CO? Or, are you advising this to let fresh air (Oxygen) into the house?

2. From my original post:

> It also has a small opening that can be opened/closed at the back of the fireplace that

> allows fresh air from outside into the fireplace; so you feed your fire with outside air

> as opposed to heated air from the house.

I'd like to crack this rear opening slightly to supply oxygen to the gas logs. Assuming that we'll get enough heat to create a draft up the chimney, do you suspect we'd get any heat out of this setup? Or would you anticipate a net heat loss (i.e. colder than having it off)? I understand that it will be much less efficient for heating the house as opposed to closing the dampers, but would be okay with this setup as long as we get some heat out of it.

3. I was initially leaning towards the direct-venting gas logs but believe that the building code will require that we clamp or weld both of the dampers open for safety reasons. Having to permanently open both dampers is a very big negative for me and makes me view the direct vent gas log option as a non-starter.

> jrb541

> ...

> I'm guessing most responses will be to avoid this type of set-up.

> That being said, I'm using that configuration in my current home. I don't use the logs a lot,

> primarily to take the "chill off" and opening the damper when I do. I also have a CO alarm

> in the room to monitor the presence of that.

So, you use ventless gas logs with the damper open? Do you find that the creates enough heat to draw air up the chimney?

> Bruce

> Are you in California, or some other location with unique code requirements?

We are in Annapolis, MD.

Check out this link - it should answer most of your questions:

https://www.thebalance.com/are-unvented-gas-log-fireplaces-right-for-your-home-1797754

Some of the non-methane components of natural gas can produce irritant vapors (various nitrogen and sulfur oxides) so if your child has a sensitive respiratory system, you may need to leave the vent open, losing some of the heating benefits of the ventless logsets.

I have had vented gas logs in a brick fireplace for over 20 years. I installed a blower with mine and do have the damper open 1/4 inch. Have co2 detectors both in the same room an in the bedroom. I use my vented logs all the time,I do have glass doors we close when not in use. I would look at vented logs if you are going have the damper open and run the ceiling fan when the logs are on to spread the heat thruout the house. They are our heat backup when we loose power.

annapolitan - i am in the exact same situation as you! what did you decide? are you happy?

basically, i have a masonry fireplace - leaving the damper open all the time for the vented logs is a nonstarter - total waste of energy. a gas insert is $$$$. looking at ventless but concerned about safety with little kids - but wonder if i could use it with damper cracked to ameliorate that risk (and close damper rest of the time). welcome all advice!

I looked into ventless insert but decided not to do it. The drawbacks i read from burning ventless gas insert are added mosture, CO2, some soots, oxygen depletion. You need to open a window or vent to let in fresh air (oxygen) so you don’t pass out or die from lack of oxygen because combustion eventually uses up oxygen inside your house.

Today's Ventless Gas Fireplace Log sets come with oxygen depletion sensors.

Greg here from Hansen Wholesale, where @tigerdunes purchased his ventless logs. I am also the one who has published all of the details at the Hansen Wholesale website regarding the pros and cons and differences between vented and ventless gas logs.

Truth is, there are many considerations and we handle each case separately when dealing with our customers. In some cases, ventless makes sense, but in most cases vented gas logs are the best choice.

The original thread here is 3 years old, but as I read the entire thread there is some confusion about welding the damper open when installing a direct vent gas log. I think Anapolitan may have confused "Vented" gas logs with a "Direct Vent Insert". There are no "Direct Vent Gas Logs". Direct vent refers to sealed metal box that you insert into the fireplace. There are two ducts that get run up the chimney with a special chimney cap installed at the top. One vent draws outside air down the chimney for combustion while the other is used for exhaust. It is an air tight sealed unit. Because there are 2 ducts, the damper would have to be propped open to feed the ducts up the chimney.

Vented gas logs require that the damper is open when they are burning. Some municipalities may require you to weld the damper open when using a vented gas log. The reason vented logs need the damper open is because they burn more like real wood where they intentionally do not completely burn the gas. This creates a wafty yellow flame very much like real wood. It also produces Carbon Monoxide (lethal gas), Carbon Dioxide, Water Vapor and Soot. Hence the reason the damper needs to be open. With the damper open, most of the heat goes up the flue.

Because ventless logs burn the gas completely, at least in an ideal situation, the byproducts are Carbon Dioxide and Water Vapor, neither of which present a health issue when used in moderation. Since the damper is closed, 99.99% of the heat produced by burning the gas will come into the room, so ventless gas logs produce a LOT of heat, sometimes too much.

The R. H. Peterson ventless gas logs are rated as both vented and ventless. Technically, if they are intended to be used as vented logs the damper must be propped open permanently, but most people ignore that.

The best solution to the issue of leaving the damper open all the time is to add a glass door to the fireplace so you can close the doors when the fire is off.

Anyways, I have much more detail on our website and in the heads of our gas log experts.

Anyone reading this may want to talk to us directly because each case really does need to be handled on an individual basis.

Profided by: Greg Tillotson

Hansen Wholesale: Gas Logs and Fireplace Doors

Feel free to email me directly. If you do, be sure to include some pictures of your fireplace along with the inside dimensions: gregt@hansenwholesale.com

P.S. If this comes through all in bold, I tried turning the bold off, but it wouldn't listen.