Well lots of people have them and are not dying in mass quantities or the fireplaces would not be legal. They are safe as long as they are properly maintained and serviced as recommended by the manufacturer.
When you burn gas, the by products are mostly CO2 and H2O, along with some good old CO from any incomplete combustion. So you will get lots of water vapor.
safe means safe to use in your home, meaning doesnt deplete air levels, safe meaning healthy
Excess means dripping windows
And I ment humidity
You can substitute the word *approved* for *safe* and they may be ok but only if you can meet the very strict code restrictions on their use. Most homes are too tight and won't qualify.
Depletion of *air* levels is a function of room size and ventilation rate. Most VF I have ever seen were oversized for the room. The code requires 50 cubic feet of room per 1000 BTU/hr input rating. That's just for normal combustion. However, in a tight underventilated room, as the CO2 builds up, it will settle to the floor displacing O2 at the burner which can lead to incomplete combustion even while a sample of room air taken waist high might read 20.9% or normal O2.
There is nothing healthy about burning gas inside a home without a chimney or vent. Just ask any building scientist or industrial hygienist. They are *tolerated* as long as they operate within IAQ stds. This is based upon laboratory in vitro testing--not in vivo testing. There certainly is no major health benefit from their burning. What humidity is initially improved from a dry house is quickly offset by the introduction of NOx, CO2, CO, aldehydes, reduction of O2 and inevitable odors.
By the time you have frank water dripping from windows you are far up the psychrometric chart. This is not a good indicator of interstitial water condensation.
I knew you meAnt humidity ---just bustin' on ya'.
FYI, *safe* is a dirty word we don't use. It is an absolute that can never be met. It can also be a relative term. Your car is probably a lot safer parked in the driveway than on the highway. Most fireplaces are safer when not used. Nobody can pronounce anything as absolutely *safe*. You might be able to say something is *suitable* for use or *approved* or *operating within mfrs. specs.* and still not be *safe*.
I believe most vent free equipment are manufactured oversea's . If you read the caution paragraphs on most non- venting equipment literature they tell you outright, may cause dizziness and or death, unless fresh air is brought in. After you meet the fresh air requirements you no longer have a good heat source but a mediocre focal point. Spend the extra money and install a vented fireplace. People that have called me in the past for an estimate I always will go out there but I only give them an estimate for a vented product. Most people that sell these units no nothing about them but the price. No nothing about fresh air requirements. Just because they sell those unvented fireplaces in those large home improvement stores doesn't mean their safe. Good Luck...
A very large percentage of my business is the servicing of vent free gas fireplaces. Most of those gas logs are made right here in the good old USA. Monessen Hearth Systems is located just outside of Lexington, KY. They make Monessen, Majestic and Vermont Casting gas fireplaces. R. H. Peterson is located In California. Heat-N Glo is in right here in Lakeville, MN. Kingsman is not overseas, but is located just over the border in Canada. The one's sold in the big box stores probably are not be made here, but the true professionals on this board would never be caught dead selling a customer a set of those gas logs.
Meeting the fresh air requirements may require opening a window in the coldest climates here in the US, but most of the homes are not that airtight and breathe enough to not run into and fresh air problems.
Here in the Eastern US, we can use extra humidity in our homes because the relative humidity is 25% in the Winter vs. 95% in the Summer.......you'll know what I mean if you know anyone that's ever had hardwood floors installed in the humid Summer and had big gaps in the flooring come Winter.
I remember when sex was safe and race cars were dangerous.
Rob, understand my intent is not to demonise VF as a product category but to find some balance. From my years of selling dozens and installing & servicing hundreds, I have come to the conclusion VF are not an appropriate appliance to be putting into homes. Here is my logic:
-the testing and listing is in vitro (lab). Under highly controlled conditions, they were able to get them to burn within acceptable limits of the Lung Assn. and ASHRAE. However, reality tells me these conditions are seldom, if ever found in homes.
-recent in vivo testing uncovered higher levels of NOx than previously thought. This is a respiratory irritant. In the doses encountered, it would cause tearing, runny nose, coughing and aggravation. Yes, the CO, CO2, and O2 were not through the roof BUT............you have to understand the controls of this study. These fireplaces were professionally installed, cleaned and maintained. The homes studied were all of rather similar construction and in the same community. No spread of climatic zones or types of construction. There were no samples taken of interstitial moisture and no walls opened up.
-There is no requirement for training of VF salesmen, installers or service techs. I don't know of a single community in the country that requires a qualified professional service tech to inspect and *certify* the logs annually. Therefore, it is the Wild West as far as what size logs are installed into what sized space with what type of construction, what amt. of Air Changes per Hour (ACH), etc. I've seen 24 Mbh burners installed into an 8x8 room. I've seen 40Mbh burners installed into small bedrooms without MakeUp Air (MUA) or ventilation.
-the safety record of VF is always expressed in terms of fatalities attributed to VF as zero. This has several flaws. First, the reporting systems in America are a joke. Unless a fire dept., fire marshal or utility report a CO-related injury or death, it does not get captured by the Consumer Products Safety Comm. (CPSC). Also, you can get floods of CO poisonings into one ED but unless someone reports the make and model of the suspected offending appliance, it does not get captured or investigated. The people who typically investigate these incidents are not qualified to do so.
Secondly, there is no reporting of illness from VF. How many people thought they had: flu, allergies, mood swings, chemical sensitivities, psychological disorders, etc. and were given Rx for the same when it was actually due to CO/ humidity/ NOx? How many asthmatics live with VF fireplaces? A bunch.
-I find it very, very rare when a ventfree appliance is clean with the logs in their proper position. Most have more hair than the cat and the logs are out of place.
-I find VF in situations where a direct vent could have easily been installed and the client was more than able to afford it. Moreover, once told of the choices, invariably these homeowners get upset that they were sold VF and not told about the DV option.
-The parameters for what would constitute *acceptable* conditions for installation are very, very narrow. Rob, I would strongly disagree with your statements about how *loose* homes are in your area. I have been in quite a few, both existing and new construction and I find the opposite. If you look closely at the definitions in the code regarding the restrictions on VF and the types of construction, you will find very few applications that fit. The old 'seat of the pants' view of tight construction just doesn't hold water any more ( or, pardon the pun, the problem is, it DOES hold water---and air!). Today, there is no reasonable excuse for not having a blower door test done to see if a house needs mechanical MUA ventilation. The energy codes are driving it this way, too, not to mention the tax incentives and low income weatherization opportunities.
As for talking points, I think you know enough about the product categories to draw your own conclusions and comparisons. Personally, I think the energy codes will drive vented gas logs out of existence pretty soon. It will be DV or electric within 5yrs I predict. I personally downsell vented gas logs because I think they have too many drawbacks. They require the damper to be removed or blocked virtually wide open 24/7/365, which is a huge energy waste. They typically require huge burner inputs to get that big pretty flame, which wastes energy. They waste more energy up the stack than they provide to the room just as burning wood does. They typically waste energy with standing pilots. They cannot be legally operated by a thermostatic control. They are typically installed too big for the Fp opening, too far fwds, and NOBODY does the requisite Level II inspection prior to installation. They can gunk up with soot and often are a source of Black Particulate Matter entry into the home. The controls typically are not service friendly and don't lend themselves to taking the appropriate gas pressures and millivolt readings and circuit readings as you would with a DV that is accessible. They seldom have the proper gas shutoff. In my area, I'd say only about 20% of the logs I find are listed and therefore even legal in my jurisdictions. That's a short list...
So, what do I recommend? Direct vent properly sized, sold, installed and maintained. It's the only way to fly. None of the problems above with half the calories...
Point of clarification; you listed Heat&Glo. For those who don't know, Heat&Glo does NOT make a gas ventfree appliance. Their only ventfree appliances are electric. As for American mfr.s, most are headquartered in the US but many have offshore or bordering mfg plants. If anyone wants to see a list of hearth mfrs., distributors, wholesalers, retailers and service companies, you can find it at www.hpba.org
To compare smoking vs. ventfree, conduct this simple test: have a non-smoker lean over a VF appliance that has not been serviced for years and inhaled deeply. Then have them take a drag on a cigarette. Now, ask them if they enjoyed either experience or want more. I'm betting while they'll cough from the cig. for sure, they won't enjoy either. So, why put either into your home or lungs? You can legally open a bottle of ammonia indoors but I don't huff it and I open windows when my Hearthnurse is sterilizing our home (daily ritual--don't ask....)
Neither me or Hearthnurse smoke (I did from '72-78 then quit cold turkey)
My intent was not to rekindle the vent free debate, I am looking for information that I can share with my customers that will allow them to make their own opinion on vent free safety. That's why I asked which you thought was more damaging to your health, cigarettes or VF.
I spend a good part of my service call educating my customers on the proper operation of their gas appliance. I understand the importance of keeping the cat hair on the cat and not in the fireplace and have implemented a program to service all of my customer's gas fireplaces annually per manufacturer's recommendations. I'm making cleaning up this city, one gas fireplace at a time !!! I am always open for input on how to better serve my customers and the fireplace community, and Hearthman, your input is not only highly respected, but VERY welcome. Hopefully some day our paths will cross and some of your infinite wisdom will rub off on me !!!
I'll do some research on the subject of the tightness of the homes here locally. A lot of the homes here were built in the 60's and only have 2x4 exterior walls with little or no insulation in the walls. I've got a friend that owns a HVAC company that would be able to give a more educated answer to that question than I.