Ventless Fireplace

Oh I hope not Nick. Y only want Roy to back up his assertions and opinions with with something truly substantional.

Nick, Are you going to be in Green Bay for WAHI in Nov.?

No but I will be at the Nov. WI-NACHI.

How useful are those WAHI-style events (multiple seminars in a day)? Are they very insightful or are they more of a refresher thing? I’m partial to day-long offerings that focus on one subject but am willing to shell out for these events if an inspector like yourself can vouch for them.

I enjoyed the one last year. I go for the CEUs.
Some of last years presentations were very good. I particularly liked the one on litigation and avoiding lawsuits given by a very HI friendly attorney.

The fireplace in question is approved and is allowed in accordance with the building and fire codes of the municipality inwhich it is located. The installation passed inspection.

So I don’t really care if someone likes them or not, I only want to know why it would set off the smoke detector.

Roy just seems to have a blind spot on this issue, which is OK, but telling people they are unsafe wen that is not fact and cannot be proven anywhere could cause problems with litigation down the line.

I posted the GAMA info as a rebuttal of your post which indicated tha GAMA didnot have any proof that they were safe (1995 study has evidence that they are).

Regarding running a vent while you run your gas burning stove/oven: we cook thanksgiving dinner in our gas oven every year (turkey goes in at 6 AM and is done around 2-3 PM). We do not run the recirculating hood vent (which is what is found in most homes, not a vented one) and no one has died from carbon monoxide at this highly dangerous family function yet.

I guess we (and millions of other Americans who cook 20 pound turkeys in their gas ovens) are just really lucky and have been for the better part of the 20th century…

Probably for the same reason that water vapor can set them off. I found this on a discussion thread which should give you some more insight. It is from a physicist/chemist in answer to a question about what sets off a smoke alarm:

More good info on smoke detectors and how they work (as well as other info) can be found here:


I’m not posting to agree one way or another,I would just like to inform my fellow NACHI members on the dangers of the products of combustion.Please read this article.And pay special attention to the symptoms of CO poisoning and it’s affects.

Good link Mario. Thanks.

What is conspicuously absent from the list below are ventless appliances of any kind (ventless fireplace, range, oven etc.) they do mention other fuel burning devices without giving any specifics.

They are addressing the need to maintain the vented appliances they list.

Are Combustion Gases Spilling Into Your Home?
Does your home have any of these combustion appliances?

  • Gas-fired furnace, boiler, or water heater?
  • Oil-fired furnace, boiler or water heater?
  • Wood stove or fireplace?
    *]Other fuel-burning device?
    If so, then combustion gases will be produced as the fuel burns.

Personally, I strongly urge the use of vents for gas ovens. I explain that CO is a potentially lethal gas produced by combustion that is odorless. I will never endorse use of unvented gas ovens but I won’t condemn them like Roy does. I stress that at the very least that the client install a CO detector near the oven so that they know when they are in danger. I’ve only encounter two unvented gas ovens and it seemed that both clients weren’t interested in installing a vent. But they were both very receptive to installing a plug-in CO detector nearby and cracking a nearby window open slightly during use.

Good advice Nick. The addition of a CO detector is always a good investment and cheap insurance. They are becoming mandatory in more and more jurisdictions even for existing housing.

I agree Nick, I have an natural gas oven with a vented {outdoors} hood I sometimes forget to use it and my eyes sometimes burn,if used for a prolonged time, these are the aldehyde’s that are produced from the products of combustion.

I would be happy if you can show me where I ( but I won’t condemn them like Roy does ). If you read my posts I show where Ventless gas Fire places are not allowed but I did not condemn gas ovens.
Many places and countries do not allow ventless Gas fire places .
All the information against my posts come from those who have an Axe to grind being associated with gas suppliers or sales .
. My only statement on Gas stoves is they usually have a vent and who would run one for 10 hours non stop.I also sudjested some one with Gas test equipment to test a gas stove with nothing on it and with a cold pot of water.
. Roy Cooke


You can say it as often as you like but that doesn’t make it true.
Joe posted some excellent info here and I encourage all to read it.

I have no axe to grind and am not associtated with anyone who does.:roll:


I think Roy is better off telling people that a ventlees fireplace is unsafe,than someone that says that it is.People [the general public] have no idea about CO poisoning,or it’s affects.Sure the utilities,Governments,fire dept. etc.are trying to make people aware of this problem,but the fact remains that very few know the affects of CO, natural gas produces the most amount of water vapor,it should be vented to the outdoors.
As you know when you burn any fossil fuel you produce products of combustion,a host of toxins.If fuel, air mixtures are not correct[incomplete combustion] and you don’t see the nice blue flame on stove or furnace then CO is produced.If mixture is correct[complete combustion] you still have trace amounts of CO.Thus venting is a good idea.It’s elementary!!!

Mario, burning a match or a candle indoors produces toxins.
The issue for exposure to toxins is the dose received.

We should be providing accurate informed opinions and recommendations not myth.


I do not burn candles, and CO poisoning is not a myth.
Roy states that a ventless fireplace is not legal here in Canada you say it is in some U.S. states all I’m saying is do you really want something like this in your home! I really don’t care how many parts /million are a safe “dose” of any toxin.Why expose yourself unnecessarily!!

You are exposed to toxins everyday of your life. Dose is the issue.
CO poisoning is not a myth and I certainly didn’t mean to imply any such nonsense. I also heartily endorse the use of CO detectors in every home in the interest of safety.

Actually ventless fireplaces and heaters are legal in 47 states and much of Europe. Properly operating ventless appliances including ovens and ranges do not produce any appreciable amounts of CO and can safely be used if the manufactures instructions are folowed.:slight_smile:


At least we agree on CO detectors!!

Maybe I’m confused - but are we mixing apples and oranges here? I thought we were talking about vent free fireplaces, not ovens.

Ovens are a different animal, and I can’t say I have ever seen a vented gas oven, although I have seen hundreds of gas ovens. Some have hood vents, but (at least in the homes I see) about 75% of these are recirculating, not vented.


Do what you like, but do not be surprized when you hear from a PO’ed seller when he wants to know why the deal died because the buyer is insisting on a vented fireplace, when the model installed is legal, proper constructed, properly installed, more efficient, and scientifically proven not to emit the gases that you alledge it does in levels that are significant.

Do you also tell people to get rid of the gas oven that is in the kitchen?

I am not here to tell you what to put in your own home - I wouldn’t have a gas fireplace because I like the smell of a real fire, but aside from that - a ventless gas fireplace is fine by me. In fact, I have had many more complaints from people with the vented kind (permanently open flues create major drafts and noises) then I have concerns over CO from people who have non-vented.

All I am saying is that scaring people about properly installed, operating and scientifically proven devices may not be a smart way to go if you want to stay out of court. Say nothing - note that it operates and that it is not vented. Explain how the unit and oxygen sensor work and what protection it offers. Recommend a CO detector as an extra precaution. Then let it be.