Vented Gas Logs

Back to the original question, I would also like to know how to distinguish a vent free log set from a vented log set.

…probably with info by the gas valve shut off and pilot it should list its ventless properties.

There is supposed to be a metal plate / tag attached to the log set. It is not supposed to be removed but we know how that goes. Many people retrofit metal insert fireplaces with gas log sets after they lose the rosy image of a cozy wood fire on a crisp winter evening. Many of those are already set up to accept the gas piping insert on either or both sides of the interior. You will see a “knock-out” plug near the bottom of the side refractory panels. Unvented log sets typically look more realistic when operating but the ventless give almost 100% efficiency, whereas the vented gas logs can actually draw heat out of the house and up the flue like any conventional fireplace does (they are about 15% efficient). There are also metal fireplaces made specifically for ventless gas logs and there is not a flue or a damper to even operate. Here is just one of thousands of websites that explain much of what you need to know and if all else fails you can call them and ask the questions you think are Germaine. Good question BTW. Many would never think to ask. Another thing to consider is whether or not the unit is natural gas or Propane. It makes a difference.

I never knew cats were approved as combustion fuel.
We always just buried them. :twisted:

On a more serious note an back on topic

In lieu of all the other things I find installed incorrectly on a daily basis and the potential for pollutant and poisonous gas emissions into the living space I refer these to fireplace experts.

Well, after reading some of these post, and seeing I have a fireplace that I don’t use because it draws like sh$t, I think going with a vented gas insert will be the way for me to go.

Interesting, topic, but there seems to be a lot of areas on these unvented gas logs that appear to be controversial as to whether or not they are completely safe.

What should be reccommended when one of these unvented units is observed on an Inspection? Are there any proven statistics on their use over the Country?

Marcel:) :slight_smile:

After 1983 all gas fired space heaters (basically what a ventless fireplace is) are required to have Oxygen sensors as part of the safety equipment. I do not know the stats on their safety record (I am sure there are some somewhere). I always recommend to our customers they purchase NEW CO detectors / alarms whenever I find gas fired appliances or fireplaces in the home. Often we find CO alarms in homes but I wouldn’t trust someone else old equipment no further than I could throw the house. There are many more safety features and back up systems on gas appliances today than when I was in my cavity prone years. It was common when I was a kid for homes to have open gas fired space heaters without any CO detection. Back then I think people were more responsible and in some ways a helluva lot smarter about safety issues. Today it is just too easy to let someone else do all their thinking for them. We have men today who can’t even find the engine of their cars, let alone fix anything on it. Just a sign of the times we live in. I have a lot of gas appliances in my home and have installed good quality detection alarms and have never yet had one go off. Probably comes from having our stuff serviced regularly and just keeping thing up to snuff. Hell, we know some people never even change an AC filter. Its like anything else; do the research, buy the best you can afford and put in safety measures and equipment.

Vent free appliances? No such animal. The vent gases have to go somewhere if not you’re turning a house into the chimney.


Could you explain your statement based on factual correspondence or literature and share with us why you are stating that. Please

Thank you.

Marcel :slight_smile: :slight_smile:

I guess those portable kerosene heaters, approved for such use, should be vented also?

I wonder what all those “ventless” gas logs, propane and natural gas space heaters that Ive been seeing and inspecting are then? I am planning on putting one in my workshop when I get around to building it. It mounts on the wall and uses IR technology to heat the room and runs off natural gas (or propane).


You are right, but here in Maine you might be faced with seeing Runtal heating elements on the walls and wonder what the hell they are. ha. ha.

So, I guess we are all here to share the different heating elements of this technological World and appreciate the education.

In the potatoes world as I was, using space heaters with kerosene was a daily
chore. It was also common as a heat source, and cooking when I was a kid,
and now it is oil heat no more wood and a fireplace that does not work. ha. ha.

Next step is a gas fired log fireplace insert with venting. IMHO

I think that the heating requirements of certain geographical areas might differ.

Venting and vent-less appliances might become more of preference than anythingelse.

Being from the cold country, we might tend to stick more with the venting, due all the fresh cold air we have up here. :wink:

Thanks for all your information on the subject.

Marcel :slight_smile:


You are welcome. Glad I could help even if just a little.

OK You have a ventless heater. Combustion produces carbon dioxide, nitrogen dioxide, and hopefully only small amounts of carbon monoxide and water vapor. Gases are hydro carbons they have hydrogen atoms. When the gas is burned only a portion of the oxygen going through the burner is converted and bonded to carbon atoms to form CO2 and CO. Some of the oxygen atoms are bonded to hydrogen atoms to H2O water vapor Where is this carbon dioxide, hopefully small levels of carbon monoxide and water vapor going? Into the home. The instructions for these heaters will state to crack a window open when using the heater. How many times is that ever actually done? That is why I say when you use a ventless (unvented) heater you’re making your home the chimney because a brick or metal chimney is where these gases should be going.

Here are some links abount unvented heaters

Used to have a link by the vent free alliance promoting ventless heaters, but surprise surprise that web site is gone. Not that I lost the link just that the ventfree alliance no longer exist.

Yes unvented heaters have been mandated in the US that heaters manufactured after 1983 have oxygen depletion sensors to hopefully kill the heater before it kills people.

If you go to the manufacturers web sites for unvented heaters they state that they cannot ship their heaters to Canada, Alaska or Hawaii.

Canada outlawed the High Temperature Plastic Vent materials years before the US recalled the material. Maybe our Canadian neighbors are years ahead of us in the US on this issue as well.

I refuse to work on these heaters.

Mr. Reecher, do you know of any deaths or injuries associated with the use of ventless gas heaters since 1983?