Q: I have an old house and for whatever reason, there is not a damper at all (never was) on the fireplace. I love vent-free logs and am planning on installing them in this fireplace. Do you make a product that I can use in lieu of having to have a damper installed in order to keep the heat from my vent free logs in the house? _ ET
A: ET, I’m sorry we do not have a heat-resistant version of the Chimney Balloon. Our product is actually designed to release if exposed to acute heat. I wish I could direct you to this issue, but your fireplace and mantel may not be well equipped to handle the heat spillage from a vent-less gas log. I wouldn’t want you to risk a fire from having heat spilling up across your lintel and mantel. You may want to think carefully if this is in fact how you would like to heat that room. – Jason
Q: I have a set of gas logs that are un-vented. Am I able to use the Chimney Balloon to completely seal off the outside air and use the fireplace at the same time? I have a damper and would keep it closed, but I would be afraid the “auto-deflate” option might kick in on me. – NE
A: Dear NE,
Even if it is a vent free gas log If you light a fire under a Chimney Balloon it will burst and deflate. The heat will sneak up past your damper and get the Chimney Balloon to its burst temperature point.
However, it does benefit you to have the Chimney Balloon in while the vent-free gas log unit is not in operation. – Jason
Q: Jason, I have a set of vent free gas logs in my fireplace. The fireplace also has a regular 18″ round chimney flue and a round metal flapper damper. If I understand correctly most vent free gas logs do not have a chimney since they are supposed to vent into the house directly to provide all the heat to the living area.
The damper on this ventless gas log fireplace chimney is worn out and lets in noise and cold air when the fireplace is not being used. Can I install a Chimney Balloon above the damper and close the damper and keep the Chimney Balloon in place even during the time I use this ventless gas log fireplace? – KK
A: Dear KK, We get a lot of questions about using a Chimney Balloon with gas log fireplaces. Especially about ventless gas log fireplaces that have chimneys. Most vent less (or vent free) gas log fireplaces do not have chimneys or flues in the first place. They are often designed to vent directly into the living area. This does allow them to give all of their heat to the living area, but it also allows them to give all of their fumes and moisture to the living area as well. For this reason I am not too keen on vent free gas logs.
To get to your question about the Chimney Balloon and if you can use it above your damper on this vent free gas log. You said your damper is leaking in cold air and noise from the outside and the damper is not in good shape. This means the leak goes both ways on your damper. Cold is coming in and heat certainly going out both during your fireplace use and when the fireplace is dormant. The Chimney Balloon is designed to shrivel and release when heat or fire is introduced to it. This release mechanism triggers at about 180 to 220 degrees. The Chimney Balloon does this because it is designed to plug the chimney flue, and in most cases it is not desirable to have a plugged chimney flue when you have a fire in your fireplace.
So if you light a fire in your ventless fireplace and the Chimney Balloon is installed above your damper (even with the damper closed) the damper itself will heat up and conduct heat through. As you said, the damper is also leaky since it allows cold air down, it will also allow heat up as well. That heat will come in contact with the Chimney Balloon. This will certainly trigger the release of the Chimney Balloon sooner or later (probably sooner). Then you will have a cooked Chimney Balloon. It is still worth it to have the Chimney Balloon in place in your fireplace when you are not using this vent free fireplace since it will eliminate the cold air and noise issue, but you cant leave it in place during use of your fireplace.
I have had many people ask: “what is safe to use above a ventless gas log to plug the flue?” Some people use safing insulation to plug the fireplace flue above a ventless gas log. I realize safing insulation is fire retardant, but safing insulation is not made for this specific purpose so this is a risky venture at best. – Jason
Jason – I converted my masonry fireplace with natural gas and installed an unvented gas log set. Can I install a Chimney Balloon above the damper, keeping the damper closed and ignite my gas logs without incurring any damage to the Chimney Balloon? The gas log set is rated at 39K but. Thanks, CB
Dear CB, If the temperature in the flue gets to about 200 degrees Fahrenheit it will trigger the release mechanism in the Chimney Balloon. Essentially the Chimney Balloon membrane melts and shrinks at the same time and the Chimney Balloon falls out of the Chimney. I’m betting that you will get heat conducting through your damper that will exceed 170 degrees within minutes with this vent free gas log turned on. Unfortunately, the metal from the damper will conduct the heat right through.
On the other hand, it will benefit you to use a Chimney Balloon above the damper when you are not using the fireplace. This is how it is normally used and it will keep your nice warm inside air inside where it belongs and not be floating up past a leaky damper.
Q: Jason – I have an old vented gas log that is crumbling and needs to be replaced. What is better to replace it with, a vented gas log or a vent-less gas log?-NW
A: NW- If you go with a vented gas log install you will certainly have to commit yourself to having the chimney damper removed or clipped or disabled in the open position according to current code for vented fireplace install. This means you will have a gaping hole to the outside
all the time. Many gas log owners are surprised to find that their fireplace flue damper has already been disabled when their original gas log was installed. The building fireplace code that states to disable the damper, is often an adequate enough reason for a homeowner not to go with any vented variety gas log.
In the vent-less model, you do get the benefit of retaining all of the heat if you keep the damper closed, but any of the CO, CO2, Nitrogen or moisture that it puts out will enter your living area as well. In the winter when your home is closed up you really want to minimize the extra pollutants you introduce to your already recycled inside air. This is not just with the fireplace, this goes for candles, sprays, paints and other pollutants. You obviously can’t avoid these items all-together, but do you want to introduce new contributors like a vent-free fireplace?
From our conversation on the phone, I am sure you have your heart set on a vented gas log, and you were just looking for brand-name references from me. But please take into account other options like electric fireplace inserts if you are looking for fireplace ambiance, or maybe even a candelabra with candles burned with the damper open as other suitable ambiance option that won’t cost you in heat loss. – Jason