As a fireplace repairman and former gas utility repairman, I strongly urge you to buy vented equipment.

If everything is working properly, unvented equipment is fine, but I've never found anyone who read, understood and followed all the numerous warnings about operating unvented equipment. Therefore I conclude that pretty much everyone who has unvented equipment is exposing themselves to risks of carbon monoxide poisoning.

I have testified as an expert witness in hearings over who would pay when a homeowner was injured by a new unvented fireplace installed in a new home. The cause of the problem was that the installer hadn't followed the rather complicated directions from the manufacturer on how to arrange the logs. That put the homeowner in the hospital with carbon monoxide poisoning.

Is that the kind of margin of safety you want in your home?

Seattle Pioneer

Here is a post that I clipped on gas fireplaces:

Posted by: renron on 12.19.2006 at 07:28 pm in Fireplaces Forum

First, DON'T install a ventless fireplace!!!
Even though the MFG.s will tell you the exhaust fumes are OK, do you really want to breathe them? Many people end up with Major Headaches and chronic breathing issues. Does it sound like a good idea to breathe burnt exhaust gasses?
B type flue(vent) pipes are dual thickness pipes. A pipe inside another pipe, suitable for use at 1" or more to flammable materials. Outer casing pipe is sealed and will not conduct air.
D (Direct Vent) type flue(vent) pipes are also dual layers but they are capable of exhausting burnt gas through the inner pipe and importing exterior(outside) combustion air for burning. Think of a straw inside a larger straw. Inside straw blowing, outside straw sucking outside air for combustion. A fan is usually used to help exhaust the burnt gasses.

Details below:
B-Vent (Natural Vent) gas fireplaces are designed primarily for decorative use. Generally they produce a larger and more realistic yellow flame. B-vent fireplaces are sometimes available without a glass window, so many homeowners are attracted to this design because of the open, realistic flame effect; some models do have a glass window so the existence of a window on a fireplace does not define its product classification. Natural vent gas fireplaces use room air for combustion and vent fumes through a vent or chimney that must terminate vertically above the roof line. The key to determining whether a B-vent fireplace will meet your heating needs is to check the manufacturer's listed efficiency rating (gas consumed x efficiency = heat output). While efficient, heater-rated B-vent fireplaces do exist, many lower quality "builder grade" fireplaces have no efficiency rating and, therefore, will not supply substantial heat. In fact, this category of fireplace will often use the greatest amount of gas at the lowest range of efficiencies. If you live in a warmer climate where you want the aesthetics of a fire without much heat, this may be the appliance for you. Likewise, bedrooms and smaller rooms may be a good candidate for a b-vent fireplace, but please check building codes to see if this class of fireplace is approved in your locality or for installation in the room where you'd like to use it. Local/national codes in some areas prohibit the use of b-vent rated appliances, especially in colder climates. Be aware that very "air tight" houses can cause performance problems with b-vent rated appliances, so please consult an experienced fireplace installer who can advise you on the proper installation and use you are considering.

Direct Vent Fireplaces offer the most features with respect to gas consumption, efficiency ratings and venting options. A direct vent fireplace will always have a glass window because these fireplaces are sealed systems using a double walled venting system. Combustion air enters the appliance via one section of pipe while fumes and moisture are vented through the other pipe. Most often, a double wall "pipe within a pipe" system is used. Subject to each model's requirements for distance and offsets, direct vent fireplace venting may be terminated either horizontally or vertically. Efficiency rating will average 65% to 84%, similar to ratings on gas furnaces. Keep in mind that these appliances must "waste" some of the heat produced to create a draft of rising warm air to evacuate the fumes produced without aid of a forced air exhaust system. Think of direct vent fireplaces as a decorative furnace: the beauty of a realistic flame with high efficiency. This appliance is great for primary or supplental heating and for emergency backup heating as most work without aid of electricity. Because this is a sealed system that uses outside air for combustion, direct vent fireplaces are usually the favored choice among those in the fireplace industry because of their greater efficiency and exceptionally reliable performance.
Hope this info helps,
I am a General Contractor.
Renron

I don't have the professional background of the other respondents, but I wanted to second [or third] their advice: in an era when many of us would really prefer that people not smoke cigarettes in our home, the idea of a ventless FP just seems wrong.

Just because you could do something doesn't mean you should.

Guess you'd better ditch that GAS cooktop and GAS wall oven because they must be unsafe too! Have owned our first direct vent unit for a year now and hate it . . . all it (Lennox Merit model) does is heat the outside and chill the room with the cold outside air coming in the top and bottom louvers. Wish we had our ventless log set back that we used for 6 years with no problems--excellent source of economical warmth! Don't let these direct vent 'gurus' scare you into buying an overpriced direct vent heat sink in your wall.

Speedmaster,
Sorry to hear that your direct vent unit is causing draughts. All I can say is, it must be that model. My 2 beautiful Mendotas and my Vermont casting direct vent certainly don't allow cold air in the room and they provide amazing heat with efficient remote control thermostats.
They replaced 2 ventless units which smelled periodically, left soot on windows and furnishings and made me nervous about gas by products in my house.
Ventless units are illegal in many places for a very good reason.

the merit series fireplaces are cheap. there are much better units then that on the market.
All the points above are pretty good, but one thing you might want to think about is that projector screen might get too hot with a ventless, or high effiency direct vent.
ventless fireplaces are not feild repariable, if you need a thermocouple you will have to send it back to the manufacture. Ventless firepaces are junk, and its one of the most upgraded fireplaces in the industry.
Vent free fireplaces ARE safe, they just look like crap and have a funny odor to them when they run.

Perhaps speedmaster raises a valid point, though: what are the efficiency ratings on gas ranges? How come the codes in so many localities used to ban ventless fireplaces but allow gas ranges?

mountainstoveguy--I know the merit is at best builder-grade, but that is no reason to market a device that leaks so much air. Come on, we're not talking space shuttle engineering here! I remain a supporter of ventless/ventfree fireplaces.

usgirl--You must have a some serious combustion air imbalances to acutally have soot plating out in your home. I'm sure the Vermont Castings unit is a real crowd pleaser (and absurdly expen$ive); what is it's advertised heating efficiency?

No takers yet on the GAS cooktop/GAS oven in the home being unsafe too?????

"No takers yet on the GAS cooktop/GAS oven in the home being unsafe too?????"

- I have a masonry fireplace with wood-burning insert. I am not knowledgeable enough with gas fireplaces to argue weather ventless fireplaces are safe or not. However, I can figure that running a ventless fireplace for 8 hours/ day in the winter is probably not out of the ordinary in homes that have them. I don't know of any homeowner that runs a gas oven or stovetop 8 hours/day (maybe 1 hour/day to cook dinner). So, the ventless fireplace can run at least 7x the length of time per day than the gas oven can run. It is the long run time on the ventless where I can see the generation of water vapor or the effects of incomplete combustion (CO) becoming problems.

Thanks garyg. I agree with you on the long burns being a potential issue. Of course no one would run a gas oven all day routinely; my point is you don't have all the scare talk from salesman about gas ranges! Why so then with ventless fireplaces?

In my experience with the ventless, you HAVE to turn it off way before several hours because it gets uncomfortably hot in the house! This happens much sooner than with direct vents because they are almost 100% efficient in returning the gas heating values to the room as warmth. Just want some balanced discussion here . . . ventless technology is not the great evil some would have you believe. Direct vents are ridiculously inefficient (but not as bad as a traditional wood bruning masonry fireplace), don't heat a room well at all, and therefore shouldn't be considered desireable. I guess they're the 'Hummer' of the gas flame crowd.

Forgot to add, the ventless do add moisture to the room. Its a byproduct of the propane/NG burning. For me, it adds necessary moisture to the house, as the woodstove I use takes so much moisture out.

speedmaster - How can a direct vent fireplace get drafty - doesn't it vent outside air only??

its a national code to not allow vent free in bedrooms. Not every town inforces it, but if your considering that, check with your local officials.
Vent frees do put moisture in the room, they also put in every thing else that is in the natural gas or propane. The also deplete oxygen, and can be dangerous if someone re arranges the logs to there liking.

Sorry to hear that your direct vent unit is causing draughts. All I can say is, it must be that model. My 2 beautiful Mendotas and my Vermont casting direct vent certainly don't allow cold air in the room and they provide amazing heat with efficient remote control thermostats.
They replaced 2 ventless units which smelled periodically, left soot on windows and furnishings and made me nervous about gas by products in my house.
Ventless units are illegal in many places for a very good reason.
>>

The air leaks you describe mean that your fireplace wasn't installed properly. Unfortunately, this isn't especially unusual and repairing it can involve removing and reinstalling the fireplace, doing it properly the second time.

Seattle Pioneer

Whow I would be real hesitant taking advice of from a person installing ventles appliances in bedroomsI bet they were never permitted or inspected
Ok I willing to take on the gas cooking stove issue Let me address your arguement if one already had an oxygen delpeation c gass cook stove and is worried about it then how can one promote adding more oxegen depleting appliances and justify that. In this discussion no one has mentioned combustion air makeup Many Direct vents also include outside combustion air
where is the combustion air comming for the Ventless unit? Itss comking from the exhausted air from the unitand the air you breath not all buy a part. If these decices are so safe then why the need for oxygen depletion shut offs If thes appliance are so safe then whay is it mandatory to install Carbon monoxide detectors with them? Yes codes are a bit inconsistant they allow for exceptions for convience such as cooking A Btw are you cooking in that Ventless stove? or logs care to compare BTUs out of a gas cooking element to a 10k ventless heater? the time ellement has been discussed stoves are used far less than ventless heaters one a few times a year for hoiidays the ovem may run 4 hours for the turkey satistics will prove that today stoves are used far less that the days of our parents or grand parents most homes have microwaves and quick meal preparation is the norm Stoves are used less then factor in toaster ovens. I anticaipate the arguement cooking is done year round well spring and summer windows are open so oxegen combustion air is a non factor. Another factor to consider when homes are closed up in winter this is the worst time of year for air quality making addind appliances that exhaust into that air even more pronounced for aiding poor air quality Let the arguement begin. My personal qualifications are I ama nationaly certified Building and Mechanical Inspector I deal with all appliances that Vent

Elkimmeg,

They were permitted and inspected after installation. here is the National ANSI code that applies. Of course each state might differ, as not all states allow Vent Free appliances at all.

ANSI Z21.11.2 Cont:Ã
Can be used in a bedroom (10,000 Btu or less) and bathroom (6,000 Btu or less) Ã Ã
Precise Positioning Logs à Ã
Fixed Position of Loose Materials Ã

I've lived for four years in my 100-year-old house that has a ventless fireplace (NOT a hundred years old!) in the living and I LOVE IT. I burn it just about every evening in the winter and it's been a lifesaver during a few winter power outages. As noted by others, it really heats the room so it's rarely on for more than four hours. I have it serviced every fall and leave the logs as placed by my contractor. I have never experienced any of the problems mentioned by others such as soot, breathing problems, etc. except an occassional mild odor when it's first fired up for the season. My only concern would be for the projector, Soyka, because of the heat. Good luck with whatever you decided!

From Consumer reports - just reporting what is written.

An unvented gas fireplace that's safely sized needn't pose any acute health hazard. But our tests confirm that these heaters contribute significantly to indoor air pollution. If you're planning to buy a gas fireplace, a vented model should be your first choice. That's especially wise if any household member has asthma or another respiratory ailment that may be exacerbated by particulate matter, or if your home is very airtight--and so will disperse the fireplace's emissions less readily.

A vented gas fireplace needn't cost more to buy and install than an unvented model, since some units require only a fairly small vent pipe that runs horizontally to any outside wall.

If you do decide to buy an unvented gas fireplace, here's how to ensure it operates as safely as possible:

* Observe GRI guidelines. Insist that the contractor not exceed them when sizing your fireplace.

* Limit its use. Though occasional extended use of an unvented fireplace should pose little long-term health risk, we suggest limiting operation to no more than a few hours at a stretch, as a rule.

* Provide extra ventilation. Leave at least one window open in the space where the fireplace operates.

* Buy only a certified package. Some fireplaces are sold as two separate components: a "firebox" and a "logset"--the component that contains the burners and logs. Ask the contractor to confirm, through the owners' manual or an American Gas Association label on the logset, that the two components are compatible. A dealer sold us a fireplace firebox with another brand's logset he claimed was suitable. He was wrong; the combination emitted higher levels of carbon monoxide than is desirable until we obtained a logset that was approved for that firebox.

* Use a CO alarm. That dealer error aside, the fireplaces we tested showed no propensity to generate any carbon monoxide (CO). Also, some models claim to shut off should carbon monoxide levels ever rise. However, we recommend use of a CO alarm with any combustion appliance, including an unvented fireplace.

I was having my plumber plumb for a gas ventless fireplace in my master bedroom (24x26). I am concerned now due to the info in the previous posts. I suffer from migraines and I am now wondering if I should just forgo the fireplace. My siding guy just put up the siding on the back of the house. If I chose to vent the fireplace that is where I would need to vent it. I would ruin what he already put up for siding. I didn't even think to check with the town I am buiding in. Yikes, I should have found this site earlier. I have question about the gas range. I bought a range that is gas on gas. Does the oven need to be vented out? I never thought about this either. I guess my plumber would tell me this week. Any advice greatly appreciated.

I've never heard of an oven being vented as normally the flames are not massive yellow and burn hotter BUT - I am certainly not an expert.

I suggest you go over to Hearth.com that place is where the fire experts are.

One thing nobody mention about ventless and I JUST found out is that they are illegal in Wisconsin and Minnesota because homes are more airtight!

Here is a link that might be useful: Rod & DJs House Building Adventure

I was struggling with this question recently also. My builder was really pushing the ventless but because of the posts here, I drug my feet on it for several weeks. Then, lo and behold, my state just outlawed them, too. Making my decision much easier! I feel much more comfortable knowing I'll be able to have a direct vent! I just didn't want to chance it!

What State are you in. Wisconsin, Minnesota and all of Canada is illegal. I know there is at least one more.

Here is a link that might be useful: Rod & DJs House Building Adventure

I had my first experience with a ventless propane fireplace last week when I stayed at a motel in the Pocono Mountains of PA. I have a masonry wood-burning fireplace at home.

I must say that it did crank out the heat but I was very hesitant on running the unit for more than 15 minutes per hour. The room had a CO detector but I wasn't sure if it was working so I limited the use of the ventless unit. I noticed that the flame turned itself off and stayed on the pilot setting after it had run a little while - must have reached some temperature setpoint. The only control was the setting for the flame. It was not a sealed combustion unit as it was open in the front with a steel grate.

I swore that I smelled gas whenever I turned the valve. Maybe it was me just thinking I smelled gas because I was nervous running the unit.