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Vent Free Gas Product Dealers, Installers & Owners
Defend Their Products

Q: After visiting your site and reading the selected letters concerning Vent-free Gas Logs and Fireplaces, I couldn't help wonder who these people purchased their units from? As it seems they knew little about vent-free gas products.

I have been in the hearth business for nine years and in that time I have learned a lot and continue to learn. 98% of our annual hearth sales are vent-free gas heating appliances.

First, proper sizing of the BTU output is very important. Despite what the customer might want .. more is not better. Especially in new home air tight construction. However, for 3 years we have been selling and installing a vent-free fresh air plus intake firebox which has literally solved the problem of airtight construction.

As far as odors are concerned there are several sources. Of course the first is new appliance burn off. However, if the smell hasn't dissipated after one hour of burn off, more than likely the customer has a ceramic (simply means molded) fiber log set and there is a fracture in one of the logs or it's broken entirely. Once the seal on a fiber log set is compromised, it will stink forever. The best advice is don't purchase a fiber log set, buy refractory concrete.

The second is what's called after product burn smell. This comes from the improper sizing of the BTU output. The other source for odors is cleaning products, fresh paint, new carpet, kitchen odors, etc. that the vent-free gas appliance picks up and recirculates

Sooting comes from several sources. Misaligned log(s) impinging the flame. Burning scented candles while operating the appliance (e.g.. Scented candles soot anyway. Add the warm moist heat from the vent-free appliance and the candles will soot 50 times more). Or not maintaining (cleaning the burners and log on a regular basis). Vented or vent-free... neither are maintance free. Occasionally, the burner may be out of adjustment. But, I have found this to be a rare occurrence.

Vent-free gas appliances are not intended as a primary heat source except in an emergency. They are supplemental to the customer's primary heating system.

However, just using it 3 hours a night through the coldest parts of the Fall and Winter, can lower their primary heating costs by up to 30%.

The bottom line to all of this, is buy from a reputable dealer who knows vent-free gas appliances and can size and properly install the appliance. You're not just purchasing a product, you're also purchasing their knowledge.

Rich Landrum
American Hearth and Home
Wednesday, September 13, 2004

Sweepy Hi Rich,

To answer your opening question ( ...who [have] these people purchased their units from? ), they bought them from vent-free product dealers like yourself, whom they assumed to be reputable.

You also seem puzzled as to why the contributors to our letters page weren't supplied with all the information about vent-free products by their dealers, stating that "it seems they knew little about vent-free gas products." Believe me, your fellow vent-free dealers know as much about their products as you do. I suspect they just omit or gloss over the negative aspects, because they're fearful that if they told each prospective customer the entire truth about vent-free products, they might not make the sale.


To illustrate, let's pay a pretend visit to the American Hearth and Home vent-free product showroom, where Rich is dedicated to making sure his prospective customers know everything there is to know about vent-free products before making a buying decision:


Prospective Customer: My furnace seems to burn a lot of gas. I'm considering installing a set of vent-free gas logs in my fireplace to heat the place instead. I see in your ads that these vent-frees are something like 99% efficient, and I figure if I use them instead of my furnace, they'll drastically lower my heating bills.

Rich: Well, you really can't use them in place of your furnace. Vent-free gas appliances are not intended as a primary heat source except in an emergency. Plus, if we properly size the vent-free logs for your house, taking into account health and odor considerations, the vent-free set we recommend to you probably won't be powerful enough to actually heat the whole place. And most importantly, you're never supposed to burn vent-frees for more than two or three hours a day. The rest of the time, you'll still need your furnace.

PC: Two or three hours? How much gas could I save in two or three hours?

Rich: Using a vent-free gas log set for three hours a night through the coldest part of the Fall and Winter could lower your heating costs by up to 30%.

PC: Wow! My house is heated by a 40,000 btu/hr gas furnace. During the coldest nights of Fall & Winter, my furnace burns 120,000 btu's of gas in three hours, or 960,000 btu/day. If your vent-free gas logs could save me 30%, I could save 320,000 btu/day! This sounds almost too good to be true: let me get out my pocket calculator and double-check.

Let's see... if this 40,000 btu/hr vent-free gas log set you've got here could heat my 1800 sq.ft. house in place of my 40,000 btu/hr furnace for three hours every night, I would save... 0%, because in those three hours, the 40,000 btu/hr gas logs would burn the same 120,000 btu that the furnace would have burned. How would I get any savings?

Rich: Good point, and right in line with our sizing policy; like I said before, for health and odor reasons we're probably going to recommend a smaller set, and smaller sets burn less gas.

PC: As I understand it, smaller sets also put out less heat, and I have my doubts that a 30,000 btu/hr heater could heat my entire 1800 sq.ft. house in the dead of Winter, but let's look at the numbers anyway: my furnace would shut off for the three hours I'm allowed to burn the logs, saving me 120,000 btu of gas. During those three hours, a 30,000 btu/hr gas log set would burn 90,000 btu, so my net reduction would be 30,000 btu. At the end of the day, I would have burned 930,000 btu of gas instead of 960,000 btu, for a net heating savings of... 3%.

Rich: Maybe we could go a little smaller yet. Try your calculations on a 20,000 btu/hr set.

PC: Will a 20,000 btu/hr vent-free log set heat my entire 1800 sq.ft. house?

Rich: Well, not the whole house, but wouldn't you be willing to sacrifice just a little comfort in exchange for big savings on your fuel bill?

PC: Possibly, if the savings were as big as you say. Let's see, if I closed off the bedrooms, family room and kitchen, turned off the furnace and fired up a 20,000 btu/hr vent-free gas log set for three hours every night, I'd save 120,000 btu in furnace gas while burning 60,000 btu with the gas logs, giving me a net reduction of 60,000 btu. For the day, I would have burned 900,000 btu instead of 960,000 btu, for a net savings of only 7%. And a large portion of my house wouldn't be warm.

And by the way, 7% is still not even close to the savings you're talking about. In fact, I don't know how you came up with 30%, because according to my calculations, even if you could sell me a set of vent-free gas logs that could heat my house for three hours every day while burning no gas at all, my heating cost savings would be just 13%. Since I don't really want to leave a large portion of my house unheated for three hours every day, it looks like my savings would be more like 3%.

Rich: Did I mention how a cheery fire can improve the ambience of a room?

PC: Yes, I suppose it would. We really don't like to hassle with burning wood, so if we install the vent-free logs we'd at least be able to have a nice fire in our fireplace for a couple hours whenever we want.

Rich: Not quite any time you want, I'm afraid. Another thing about vent-free logs is, there's times when you really don't want to burn them.

PC: Like when?

Rich: Like after you paint. When paint fumes hit the flames, it stinks to high heaven.

PC: We don't paint all that often, so if that's the only time we can't use our logs, that doesn't sound too bad.

Rich: Well, there's actually other times when you don't want to use vent-free logs. Like for a few days after you install new carpeting. Or when you're using cleaning products. Or room deodorizers. Or hairspray. Or whenever you're cooking. Or when your dog or cat is in the room: burnt pet hair smells to high heaven. And you don't want to try to mask the smell with scented candles: scented candles are sooty enough by themselves, but a burning vent-free will increase the amount of soot in the room from those babies by about 50 times!

PC: Wow. Are there any other times I might not want to use vent-free gas logs?

Rich: Only if you give any weight to the recommendations of the American Lung Association, the Center for Disease Control, the Emissions Protection Agency or the Mayo Clinic. According to them, you might want to avoid firing up vent-free logs whenever there's any young children, small animals, pregnant women, senior citizens, or people with diabetes, asthma or cardiovascular problems in the house.

PC: Sounds like there might be health problems associated with vent-free gas logs. Are they dangerous?

Rich: Not to worry, each of our vent-free log sets is equipped with an Oxygen Depletion Sensor. If the emissions from the vent-free in your home build up to anywhere remotely near the level that could kill you, the ODS senses the low oxygen level and shuts off the flames. I'll admit I've read cases of headaches, lethargy, nausea, nosebleeds and lung disease, but there's never been a single reported case where anybody actually died.

PC: My house is pretty tight. What if the exhaust builds up thick enough during my three hour burn to bother me or my family. What do I do then?

Rich: You can simply open a window, or open the fireplace damper an inch like you'd do with a vented set. Of course, if you open the fireplace damper, the exhaust will go out the chimney and take the heat with it, so we recommend opening the window.

PC: We're talking about the coldest nights of the Fall and Winter here. Wouldn't the introduction of cold air into the house affect your advertised 99% heating efficiency quite a bit?

Rich: I suppose that would depend upon how cold it was outside at the time.

PC: I guess you're right, it's not always THAT cold outside. You know, when I think about it, I can imagine times late at night when Granny and the baby have gone off to bed and the pets are outside, and we don't have any company over who might have health problems, and we're not smoking or cooking or cleaning or using any aerosol products or room deodorizers or candles, when we might want to open a window and have a nice, cheery fire. I like the looks of the set in this magazine picture I brought.

Rich: You don't really want that set. Those fiber logs might look more attractive than the cast refractory concrete logs, but once the seal on a fiber log in a vent-free set is compromised, it will stink forever. We recommend refractory concrete logs, like the ones in the set we're burning right over here.

PC: I guess I could put up with the looks of the concrete logs, but where are the glowing embers, and what's with those flames? The set in this picture looks much better than that one you're burning.

Rich: Those are vented logs in that photo. I'll have to admit, you're not alone in your opinion that vented logs produce a much more realistic display than vent-frees, but there's a good reason for that. Vent-free sets can't have the tall, yellow flames that vented sets have, for odor and health reasons. They also can't have glowing embers under the grate like vented logs do, as this can cause sooting with vent-frees. We do have a few sets that simulate the glowing ember effect in a different way, without risking a sooting problem. The glow is on top of the burners and grate instead of down below where it would be with a real wood fire, but it still looks almost as realistic as the glowing embers you'd get with a vented set.

PC: I suppose I can live without the natural-looking flames and glowing embers. One more thing though: I've heard that vent-free logs require a lot more routine maintenance than vented logs. Is that true?

Rich: How much and how often the vent-free log set is used determines how often it should be cleaned. Vent-free gas-heating appliances do not generate dust, but are a magnet for it due to the way they operate from natural convection currents of air in the home. We recommend the burner and grate be cleaned a minimum of every 4 weeks during the heating season and again the following fall before start up. It is an easy procedure that takes about ten minutes and can be likened to changing the filter in your central heating system on a regular basis. Unlike vented log sets, vent-frees require this monthly maintenance, because an improperly maintained vent-free set can rapidly soot up your house.

PC: Well, I don't have to change my furnace filter six or seven times per heating season, but I suppose I could find the time to service the vent-free gas logs that often. I sure wouldn't want my house all sooted up! Sooting sounds like a nightmare: if it ever happened to me, how would I clean up the walls and furniture?

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Rich: Trust me, you don't want to go there. We suggest you religiously adhere to the maintenance schedule.

PC: So, if I perform the maintenance on my vent-free log set every month, I won't have to worry about sooting?

Rich: Lack of maintenance isn't the only thing that can cause sooting. Aside from the scented candles I mentioned before, another thing that can cause sooting in vent-frees is improper log placement. If the flames impinge upon the logs, it causes sooting.

PC: So who sees to it that the logs are placed correctly?

Rich: Our technicians are very meticulous about exact log placement at the time of installation.

PC: But who ensures perfect log placement after I remove them to perform the monthly maintenance?

Rich: You do.

PC: And how will I know if I didn't place them right?

Rich: Every time you don't, your walls and furniture will quickly get covered with a layer of soot.

PC: You know, given all the facts about vent-free gas logs we've discussed, I think I'd feel more comfortable with gas logs that are sealed away from my breathing space so they vent their exhaust outside and don't burn up my oxygen. Then, I could burn them all day every day if I wanted and heat my house without worrying about bad smells, health problems or sooting. Do you sell those?

Rich: Not exactly. You're describing a direct vent insert, and we don't carry them. However, if it's the oxygen depletion that bothers you, some of our newer models offer "fresh air plus intake fireboxes" to stop them from burning the oxygen out of the room. If you don't like the idea of gas exhaust coming into your house, we now have some models that are cross-approved for partial or total outside venting. The only drawback is, if you install a vent-free appliance with these options, you lose the heat.

PC: Well, I guess I'll be going then. Thank you for your honest answers; without the information you've shared, I might have bought vent-free logs!


#2: A letter from a professional installer:
November 16, 2005

Hi there sweep, I have been installing ventless fireplaces for seven years. During this time I have lost count of the number but it is about 148-175 per month right now. It has not always been so busy but like all contracting companies peeks and valleys. Well, to the point I am a gas specialist and install both unvented and vented boxes. I not only put these inserts in but very often convert woodburners to depending on the customer vented gas logs or ventless gas logs. I always go by the book and use as much information as possible to help my customer design a system that will fit the life style and room size that they have. yes tightly built homes are harder to feel out than drafty old house but, if these people that are having problem with there systems think they are the majority, I am here to set the record straight. There are some states that do not sell ventfree hearth products. But not as many that don't as there are that do, and I know for a fact that water vapor and CO that everyone always talks about is so misconstrued, for every cubic foot of gas that is used there are two cubic feet of carbon dioxide, one cubic foot of water vapor, and one to one and a half cubic feet of hydrogen so with that said this is for natural gas. This is going to be produced from any ventless system the numbers are higher for vented because these systems can be forty to sixty percent efficient. With propane we do not measure the gas in cubic feet but if in pounds and it goes something like this one hundred pounds of gas per every two pounds of carbon dioxide, one pound of water vapor, and about one pound of hydrogen. the ventless gas logs are limited to 40,000 Btu/h and if anyone has a system putting out more than that should contact the company that installed the system. also if there is the wrong gas supply to the logs on ventless there will be sooting. I cannot make these people on your site change there minds about ventless gas products, and I feel very sorry from what I read and the problems that they have had or may still be having. But in my personal experience it is much safer to have ventless fireplaces burning properly in your home than to drive on the roads in America and be around drivers on cell phone. Also i have been to many large cities on the east coast and seen first hand the air pollution that we are breathing just being outside so maybe you would like to put a chimney on the world or that car that smokes and produces carbon monoxide which for the record is the one that will kill you. thank you for having a site that people can go on and express there experiences but I feel that you should at least post the numbers of satisfied customers with ventfree versus the select few that has had problem systems or unintelligent companies that put the systems in.

my name is Joe Willoughby

Sweepy Hi Joe,

After several readings of your letter, I'm convinced that the point you're trying to make is that vent-frees are OK with you, but I am actually not sure what your arguments might be to support that opinion. If I read you correctly, you make the following points:

1) You're aware that vent-free fireplaces produce CO gases, hydrogen and water vapor that vent directly into the house (although you're a little hazy about the exact quantities, and skip over a few nasties like nitrogen dioxide).

2) You have personally exposed thousands of households to these gas exhaust components by installing vent-free fireplaces in them.

3) You think this exposure is safer to the occupants than driving a car, especially when the other drivers are using cel phones.

5) You think the outside air in many large cities on the East coast is more poisonous than the air inside the homes in which you've installed vent-free fireplaces.

6) You're aware that only some states have banned the installation of vent-free fireplaces.

Joe, I know from you letter that you make your living installing vent-frees, and am sure you must somehow need to justify that occupation to yourself, but let me ask you this: don't you think your customers who have just endured polluted city air all day, and then survived the drive home in rush-hour traffic surrounded by cel-phone users, deserve to come home to an indoor environment that isn't polluted by the gas exhaust from a vent-free? Even if vent-frees haven't been outlawed in their state?


#3: In defense of Vent-frees: nearly two years without a hitch
Thursday, February 1, 2007

It simply amazes me how you have distorted the facts on your website with regard to vent-free products.

Get the real facts at :

I doubt you will add this email to your posted list of letters that you so pleasingly paste on the site. You certainly are entitled to your opinions, but you should offer up the ability for the consumer to read the other side of the argument and come to their own conclusions.

I have been running a freestanding natural gas fired vent free stove for close to 2 years without a hitch. I have NO soot issues, NO fume issues and it performs flawlessly.

Your constant QUOTING of the same old studies that are well outdated is pathetic.

Did you happen to make note of the fact that the American Lung Association has a partnership with the 3 brands of Hearth and Home Technologies? HHTI receives much visibility with this partnership which promotes their products exclusively! Sounds a little fishy to me. Yes folks, HHTI does not sell vent free products......a likely decision given the fact that they are in bed with the ALA.

FOR THE RECORD: HHTI is the biggest outspoken critic of vent free technology! Gee, I wonder why.

Again, I highly doubt you will post this message because it helps expose the sham against vent free that you are so proudly a part of.

Let consumers read both sides of the argument and make their own decisions. They have seen your side of the argument, let them see another side!

Aaron Abelha

Sweepy Hi Aaron,

We're just as pleased to "paste" your letter on our site as the other letters you see here and on our vent-free complaint letters page. We're glad your vent-free is performing flawlessly, and that you have no soot or fume issues with it, but if you read the other letters on that page, you'll learn that others have not had the same happy experience.

For the record, Hearth & Home Technologies is not a "partner" of the American Lung Association. HHT is one of the largest manufactures of hearth products in the country, offering three extensive lines of gas products, all vented. This industry giant has taken a strong and very vocal stance against vent-frees in the home. The ALA has taken a similar stance against vent-frees, and advises visitors to their website to choose vented gas appliances. Although we're in total agreement, we're not "partners" with either the American Lung Association or Hearth & Home Technologies.

Also for the record, the link you included in your letter (twice) is to the Vent-Free Gas Products Alliance website. The VFGPA is an organization comprised of manufacturers of vent-frees, and it is not surprising that their entire website is devoted to pro-vent-free material: selling vent-frees is their business.

You challenge the facts presented on this website, and accuse us of quoting "old studies that are well outdated." You don't seem to have subjected the Vent-Free Gas Products Alliance website to the same scrutiny:

As evidence that vent-free products don't adversely affect indoor air quality, the VFGPA website repeatedly cites the same study, performed by AGAR back in 1996.

This was not an independent study: it was commissioned and paid for by the VFGPA. In contrast, the letters that appear on our website were sent in unsolicited.

The AGAR study was not a real world study: the findings were arrived at by means of computer simulations, using data supplied by the VFGPA. The complaint letters published on our website are all from real owners of vent-free products.

The AGAR study happened over ten years ago. The oldest complaint letter on our vent-free complaint letters page is newer than that. The latest one came in last Saturday. Whose studies are outdated?


#4: Aaron again, in defense of vent-free dealers and engineers
Date: Sunday, February 4, 2007

You guys will NEVER be at MY service. I value my dealer who keeps himself well informed through research, staying current with product design changes and improvements and who gives me fair and balanced information from both sides of the fence without letting his personal opinion turn into a crusade. You guys make it seem like all of the engineers that have continuously improved and developed vent free technology don't give a crap about people's health and safety and are only interested in making a profit. Thank God that people with real knowledge and expertise have taken the time to develop, refine and scrutinize the product which has given us, the consumer another choice in home hearth solutions.

The fact remains that for some reason you are on a personal crusade against the product yet the facts have proven that if you use the product as it was designed, install it exactly to the specifications by the manufacturer, keep it clean and use it ONLY as a secondary source in rooms with planty of volume they are absolutely fine.

Aaron Abelha

Sweepy Hi Aaron,

We think the engineers who design vent-free products do it because that's what they were hired to do, in much the same way as engineers working for the military design nuclear weapons. We don't for a minute think that they "don't give a crap" about people's health and safety: we think they do as good a job as they can to make vent-frees as safe as possible.

We just don't think that's safe enough.

Speaking of jobs, something about the vehemence of your pro-vent-free stance and some of the phrasing in your letters (home hearth solutions?) has us wondering: you wouldn't be employed somewhere in the vent-free hearth product industry, would you?


#5: Aaron again, on censorship and cooking turkeys
Date: Wednesday, February 14, 2007


No I am not in the hearth business. I am an IT professional. The verbiage I have chosen is likely due to an increase in my vocabulary as a direct result of a consumer doing smart research on both sides of the debate over a 4 month period before pulling the trigger on a vent free stove. I chose the words "home hearth solutions" to cover freestanding, built-ins and fireplace inserts as a whole.

You showed your true colors with your inquiry into my profession and your undertones surrounding my stance on vent free. You need to look in the mirror. I'm not the one using the internet to stand on a soapbox as the messiah of doom regarding vent free. You are the one doing that so proudly. I am simply defending something I believe in as a consumer and I frankly can't stand to see your scare tactics posted without debate.

Be sure to open up your windows when you cook your next chicken or turkey dinner. That gas stove will put out more harmful contaminents than my Honda automobile does in a weeks worth of driving.

Aaron Abelha

Sweepy Hi Aaron,

To tell the truth, we haven't published your third letter before now as a kindness to you. But, since you insist, your letter appears above, and our response appears below.

It was never our intention to publish an unbiased web page about vent-frees. We're biased against them, and make that perfectly clear on our website page titled Vent Free Gas Appliances - Our Opinion. For the record, here's a short list of others who publicly share our bias:

Consumer Reports Magazine
The American Lung Association (ALA)
The Center for Disease Control (CDC)
The Environmental Protection Agency (EPA)
The Mayo Clinic
The vent-free owners whose letters appear on our
vent-free complaint letters page.

You state that our anti-vent-free bias is the reason you're so perturbed, yet the Vent Free Gas Products Alliance website you cited in your first letter above is about as far from unbiased as you can get. Thanks to you, we now have a link to their website on our website: do you think you'll ever find a link to our website on theirs?

The only positive factor we can come up with about vent-frees is that they can be easier and less expensive to install than vented products. In our opinion, this is one case where cheaper is not better.

As to unvented kitchen ranges, we have published our stand against them on our website, where we also make the point that all the gas ranges we sell are vented. And even if you're trying to make some point about unvented kitchen ranges in your letter above, your comparison to "weeks worth of driving" in your Honda is patently ridiculous. To validate that comparison in an indoor air quality discussion, you would have to park your Honda in someone's kitchen! And that person would likely not survive your experiment.


#6: Massachusetts Contractor says Vent-Free OK
Date: Saturday, November 3, 2007

Hi there,

I stumbled on your site looking for info on vent free fireplaces. I'm a builder in Massachusetts and our state, according to the the fire chief, and building commissioner in my town, does allow vent free stoves and fireplaces. You might want to update your site info.

For ten years now I've been installing vented fireplaces, they're a nice feature but are very inefficient. I tell most of my buyers to use them sparingly. I'm considering putting in vent free units instead, they're much cheaper, can be placed on an inside wall, and are very efficient.

Houses, even new houses, are not as tight as everyone thinks. Certainly tighter than a 17th century home, but plenty of breathing room. I install vented gas boilers in all my homes and these boilers all use internal air for combustion. I used to install oil burners, again using house air for combustion. I've never had a problem with either system type in 20 years, and our inspectors require no "make-up air" systems

I personally use two pro-com, 25,000 btu, vent-free gas heaters. One in my home, and one in my 14x16 pool cabana, that we use all winter. I'm a safety nut, and have hard wired, as well as digital plug in, co2 detectors everywhere. I've never seen a digital reading above zero, it's like they're broken. Even after hours in the cabana. I also don't understand the problem with moisture, if anything we like the moisture in the winter, the air is very dry here.

At first glance the letters on your site are horrifying, but after poking around awhile, your number of letters in opposition to vent free, proportional to those for vent free, seem quite unbalanced. I can't imagine that for every experience like mine, there are ten people going to the hospital with lung problems. These units would be outlawed everywhere in seconds if this really was the case.

I haven't looked at what you folks sell, but I'm guessing by the name you folks like chimneys. If your goal is to run a biased site that's your prerogative. I just haven't experienced, nor has anyone else experienced that I know, the types of problems your contributors are having. Hell, we have a gas cooking stove, and with forty people over for thanksgiving, that stove, with two ovens, goes on at 5:00 am and runs till 2:00 pm, with most of the top burners going. What's the difference between a vent free gas cooking appliance, and a vent free heating appliance?

Joe Brennan

Sweepy Hi Joe,

Thanks for the input! The State of Massachusetts loosened their absolute prohibition of vent-free products a bit in 2004, but still prohibits installation in bedrooms or bathrooms, or as the sole source of heat in any room. Unless you've got a source of heat other than the vent-free in your cabana, Massachusetts law would prohibit that installation.

I don't know what brand of vented fireplaces you've been installing for ten years, but your use of the term "inefficient" just doesn't hold water in today's marketplace. We sell furnace-rated direct vent gas fireplaces that achieve up to 86.4% delivered efficiency. Hundreds and hundreds of our customers heat their entire houses with their vented gas stoves, inserts and fireplaces, and many have reported that they experience significant savings over their gas furnaces.

The vented gas and oil boilers you install might certainly find adequate combustion air in even a tightly constructed house. But, unlike vent-frees, those boilers vent their exhaust outside. Vent-frees not only consume the oxygen from the room, but also foul the remaining air with CO, CO2 and NO2 gases.

Today, more and more health care professionals are becoming concerned about chronic exposure to CO levels below 30ppm. If you purchased your CO detectors after the year 2000, they won't even measure CO levels below 30ppm.

The main difference between unvented gas cooking appliances and vent-free gas heaters is daily exhaust exposure. A household gas range produces the exhaust from an average of 6,400 btu of gas per day (this average is computed on an annual usage rate, and includes the peak usage season during the Holidays). Even if you limit your usage to the recommended three hours per day, each of your small vent-frees introduces nearly twelve times that much exhaust into your breathing space. In just three hours!

Another factor about cooking with gas: these days, most gas ranges are installed with exhaust vent hoods, and more and more states now require them for all new installations. When used with an exhaust hood, a household gas range causes zero daily exhaust exposure.


#7: Why don't we publish letters from industry pros?
Date: Friday, October 10, 2008

Dear ChimneySweep Company:

I have spent the better of 2 hours reading your reports concerning vent-free gas logs and fireplace installations. I ask that you add my comments to your website both in your column on the pro and negative portion of the reader's rebuttal page. About me: I have been involved in the hearth industry a bit longer than your company, having first started in the business in 1969. Over the past 39 plus years I have specialized in new chimney construction, chimney restoration including major restorations of historic properties with stainless steel, terra-cotta tiles and cast in place liners. Installation of wood stoves began in 1973 and the cleaning of chimneys and fireplaces in 1975. Retail sales of hearth products followed also 1975. Our company's staff performs all aspects of installation where allowed by law, in the hearth arena.

I am from Massachusetts an oil dependent state. Installation (not sales) of vent-free appliances were not allowed in our state until 2004/05 as they were in all the other New England states several years prior to this date. Thinking myself progressive, I had commenced a substantial amount of research into vent-free applications, assuming that the legal installation of them would have been approved many years earlier than had occurred. We have sold vent-free products, primarily Empire's White Mountain Hearth products since they were approved. We also sell vented sets by Peterson, Mendota, Valor, Monessen and other notable reputable hearth manufacturers. Empire produces almost all of their vent-free logs also as vented sets. Every set sold in Massachusetts MUST BE Mass approved in addition to CSA approved, unique to the country, I may add. Our customers have the option of installation in either manner when used in an approved masonry or zero-clearance fireplace. Not so when the appliance is a box and log combination or one manufactured solely for use as a free standing vent-free stove or fireplace system.

We are extremely safety conscience and inform our customers of all the DO NOTS associated with vent-free installations and use. We refuse to sell vent-free appliances and logs to those who may have health issues, are sensitive to smells and odors, want to install in a bedroom/bathroom, have a extremely tightly constructed home or plan on using a vent-free for extended or whole house heating. Being objective and knowing that we are not the authority having jurisdiction on the sale, installation or use of the products we sell, we feel it is un-American to dictate to our customers what choices that they LEGALLY have via the laws of the Commonwealth of Massachusetts to make an educated and informed decision as to what would be in their best health and economic interests in the considerations of purchasing a new heating appliance. We do not install the logs or fireplace units (We do offer installation of vented appliances) of vent-free systems via the laws in our state that state that all gas appliances must be installed only by a licensed pipe fitter or plumber. While we work closely with several plumber/pipe fitter who we feel are competent, we find that unfortunately, many of the pipe fitters/plumbers/LPG certified technicians, have less knowledge than those of us in the hearth industry as to proper log placement, sizing/venting requirements and other factors involving hearth products, due to the education that perhaps companies like yours and mine strive to continue educating ourselves for the benefit of our customers.

I am not pro or anti-vent-free. While I think your site offer a viewpoint and useful forum for those considering the installation of a zone heater, and I think your replies are sincere and intelligent, I did note a lack of testimonials being present from hearth industry leaders and other informed parties. How so. A good example is the link to Consumer Reports magazine. I carefully read the earlier issue you recommended and the updated one in 2008. Trying to be as objective as possible, it is clear to me that they DO NOT, suggest the banning of the use of vent-free appliances. Further, as both of us know, Consumer Reports while not accepting advertisements, is still a for profit entity. Being heavily involved in the sale, repair and assembly of Barbecue appliances, we have found that the folks at CR are anything but perfect in the manner in which they recommend products to consumers. They hardly if ever do follow-ups to their recommendations, don't take in account warranties, customer service quality or the reputation of the companies products that they highlight as "their best buys".

As for the many entries from dissatisfied folks who claim property damage or personal injury due to use of vent-free products, I do not see documented case in support of your positions from an authorities in the health care industry, government regulatory agencies, officials of the National Fire Protection Association, the HPBA that you belong to and support, U.L Labs., Warnock Hersey, Omni Test Labs or for that matter CGA (AGA). Further, not one CEO of the National Propane Association, Hearth Industry, or other experts in the hearth and gas industries, has added comments in support of your viewpoints or those that oppose them.

Take a breather, no pun intended. Support your arguments for the benefit of those you claim you want to save from the harm of using vent-free appliances, by providing testimonies by leaders in our industry who support/do not support your viewpoints.

In closing, while I'm personally always in support of contrasting viewpoints as submitted from other seasoned professionals, it does bother me that your site is lacking credible testimonials from the who's who in our industry. They in my opinion would NEVER tolerate a "cover-up" of the sale of any unsafe hearth product. I just think you owe your readership an explanation as to why you ARE NOT providing testimonials from those trade professionals mentioned in this letter.

Viewpoint respectively submitted by,

Gary F. Bertassi, President
Griller's Hall of Flame

Sweepy Hi Gary,

Man, after spending over two hours reading our vent-free letters page, you obviously spent a great deal more time composing your very detailed letter above. I thank you for your participation in this debate.

I'd like to comment on the four major points highlighted (by me) in your letter above:

I admire your statement that you refuse to sell vent-frees to people with health issues, or who are sensitive to smells, or who want to install them in bedrooms or bathrooms or in super-tight homes, or who want to use them for extended or whole-house heating. However, other than the bedroom or bathroom location, I wonder how your showroom staff determines the health status and odor sensitivity of family members and guests, house "tightness" or eventual daily usage time.

I submit to you that it is impossible for your sales staff to make those distinctions with any accuracy whatsoever. For one thing, what would motivate a shopper who has made up his or her mind to buy a vent-free to tell your salespeople anything that would queer the sale?

I also find it interesting that, given your evident concern for the well-being of your customers, you sell them vent-frees with full knowledge that they will be installed by "pipe fitters/plumbers/LPG certified technicians, [who] have less knowledge than those of us in the hearth industry as to proper log placement, sizing/venting requirements and other factors." I understand you to say this is Massachusetts State Law, but find it hard to accept that a retailer who is truly concerned about the health and safety of his customers would continue to sell vent-frees in light of that situation.

Your statement that you disagree with Consumer Reports Magazine's anti-vent-free recommendation because you also disagree with their recommendations about barbecue appliances is pretty sideways logic, to my way of thinking. As a long-time subscriber, I must say that I haven't completely agreed with every CR recommendation over the years, but that doesn't mean I disagree with all CR recommendations.

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Finally, the answer to your question about why we ARE NOT providing testimonials from trade professionals is simple: we do publish them. Except for the many repetitious questions we get that are already answered on our site, we pretty much publish every letter we get.

If you'll revisit our vent-free letters page, you'll find letters from the following industry professionals:

Tim Rethlake
Vice President, Business Development
Hearth Technologies
(Manufacturers of Heat-N-Glo, Heatilator and Aladdin Products)

Xanndra Boehler
Hearth Products Retailer

Donerae Testa
The Place
North Royalton Ohio
Hearth Products Retailer

Bob Kirr
30-year Gas Service Technician

Beth Koesterer
HVAC Dealer

Sales at FiresideStone
Hearth Product Retailer

Perry Bumpers
Fireplace creations by BMC
Hearth Product Retailer


#8: Loves her vent-free, thinks this website is "unbalanced."
Date: Friday, December 5, 2008

I don't sell these, install them for others, or in any way profit from them. I'm just a 35 yr old SWF who happened to stumble across your unbalanced website. I installed vent free units in each of my last two homes. I love them. They reduce my heating costs by around 25% and I get to enjoy the cozy, beautiful fire. I don't maintain them aside from vacuuming the dust off occasionally. And frankly, they're the cheap ones. These things aren't for heating your whole house! I use mine because the living room gets cozy in just minutes and I don't have to heat the whole house to 70 to be comfortable when I'm going to be in one room for a few hours.

I have a 1200 sq.ft. house and a vent free unit designed to heat up to 1000 square feet. There is no blower - so it saves on electricty too. The heat spreads around and seems to keep the whole house warmer than the thermostat setting, but the LR is noticeably warmer. AND - the moisture is such a relief since winters with gas furnaces are usually very itchy!

Also, your new airtight homes have been shown to be unhealthy in more ways than one. Houses need to breath. Stop wasting trees and covering land in vinyl and concrete and live in a house that already exists. If your house is that airtight your heating costs are already 30% lower. Use your brain - if you want to hold 100% of the heat created from burning something in your house and never let any fresh air in your houses for fear your fake air might escape and natural air might get in - you're going to have bad air. I feel sorry for those who just didn't know better, but no need to bad mouth an industry just because you have a product that is not appropriate for your house.

Shannon Boone

Sweepy Hi Shannon,
Thanks for your input! We've published your letter just like we do pretty much every letter we get, and you'll be happy to know it helps the "unbalanced" status between anti-vent-free letters and pro-vent-free letters a bit.
The ratio is now 110 / 8.

We're not sure where the adversarial tone in your third paragraph is coming from, as we're not in favor of airtight houses either. Everybody needs a little fresh air in their home breathing space: that's one of the reasons we're not fond of vent-frees, which burn up oxygen and replace it with poisonous gases.

We also can't figure out how you might be computing your 25% heating savings. Even if your vent-free was able to achieve 100% efficiency and your gas furnace was only 75% efficient, the only way you could experience 25% heating savings would be if you stopped using your furnace entirely, and heated strictly with your vent-free all day every day, which you say you don't do.

Finally, and most importantly, your statement that you don't maintain your vent-frees except to "vacuum the dust off occasionallly" is just flat frightening. Please consult your manual, and call in a professional to service your vent-frees as recommended. We don't want to have to publish your next letter on the anti-vent-free page!


#9: Thinks we're idiots
Date: Monday, January 12, 2009

I need to respond to your Sweeps Magazine pros and cons on vent free gas fireplaces. First I must tell you Iam in the process of trying to prchase a gas fireplace while first doing research on air quality.I am a very impartial and objective individual. I have just intensly read your back and forth banter of opinion in response to the "pros" whom endorse ventless gas fireplaces. while I will probably end up purchasing a vented unit since there is most definitly some controversy on the safety facts I will always be a very cautious individual. But I must tell you, that after reading your posts of rebutal I have definity made up my mind that "you" Sweep Magazine are idiots! Please feel free to post MY OPINION! You need to put your writings before a nuetral entity before you continue to disway people like myself who look to so called professionals for expert advice. Unfortunately I have recieved none from your company.

Dennis Galante

Sweepy Hi Dennis,
We must admit it is particularly painful to be called idiots by someone who manages to squeeze eight misspelled words and four grammatical errors into a one paragraph E-mail, but I suppose we'll get over it. In the meantime, we're glad you somehow got the message that vented fireplaces are the way to go.


#10: Gas Log Salesman finds our vent-free complaint letters page "laughable".
Date: Friday, September 25, 2009

I recently came across your website while looking for something on a totally different subject. I began reading postings that you have apparently allowed or posted yourself on your site. Now, I work at a store currently that sells both vented & vent-free gas logs. I don't make a penny difference regardless of which one I sell. I have worked the last 17 years in emergency medicine. The claims that I see written in the forum are crazy at best & reckless at worst. We sell more gas logs, as well as many other products, then most others combined in a 100 mile radius. People claiming to have contracted "black lung disease" & having family members diagnosed with CO poisoning postmortem is something I would expect to see in the new White House healthcare proposals. I would never say that bad burners or defective valves could not possibly cause any health related issues but what you are posting is laughable. These logs have been out for almost 30 years & now 49 out of 50 states approve their use. In 99% of the cases of any issues regarding vent-free products that we investigate, almost all of them are operator error with just a couple of instances of being product issues. I believe it is reckless to put the information on there that are accusations from customers without any proof that any of what they're saying is actually true. I could say I was getting intimate with my wife in front of the fireplace & the vent-free logs gave us an STD! That's what a lot of what you have on there sounds like to me.


Jimmy Kinney
Southern Home & Hearth, Inc.
Huntsville, Alabama

Sweepy Hi Jimmy,
We respect your status as a 17 year veteran in emergency medicine, but aren't quite willing to accept that it qualifies you to diagnose the claims you read on our
vent-free letters page as "crazy at best & reckless at worst", and even "laughable", as you state above. These are real letters from real people, all suffering from similar bad experiences (like water damage, mold, mildew, health problems and sooting in the house) related to the use of vent-free gas products. We find nothing in any of the complaint letters that indicates the writers are crazy or reckless. And we certainly don't consider their problems laughable!

Your statement that 99% of the vent free issues you investigate are due to operator error begs the question. Operator error is, it seems, an unavoidable result of the human condition. The point is, vent free heaters provide a myriad of opportunities for operator errors, and these errors often have particularly dire results. Consider the fact that with vented appliances, operator error does not result in water damage, mold, mildew, health problems or sooting in the house.


#11: Jimmy again, clarifying his position
Date: Wednesday, September 30, 2009

I'd just like to clarify a couple of points. I am by no means claiming to be an expert in medicine, physics, chemistry or any related field. The "crazy," "reckless," or "laughable" comments were not directed at any consumer but at your website or any website that puts out information that has no scientifically-based proof behind it. This includes our website. In the two years I have managed our website, I have removed three separate pieces of information that I posted because I found that the info was either incorrect or not based on credible sources.

I will say that I sent that email before I realized that you also had pro-vent-free letters posted. However, I also noted that you had posted responses to most of the pro-vent-free letters doubting their validity. Then I went to your main site page & realized that you don't sell vent-free products. That pretty much explained that. While I understand that you don't feel any of the consumers health problems are "laughable," & I don't think anyone's sickness is "laughable" either, you obviously weren't equally as concerned about the people who thought vent-free products were beneficial.

Finally, I fully agree that the more restrictions you place on a product, the more opportunities people have to mess something up. However, to say that the vent-free products were the cause of mold, mildew, water damage, sooting, etc., in the large numbers that were mentioned in your forum are misleading. There may be lots of complaints but how many of those complaints are legitimate? Also, I can't speak for other parts of the country but we have regular contact with various departments in local government as well as contracting & insurance companies & these are very rarely issues around here. I'm not saying that these problems can't occur but some proof would be nice if these kind of statements are made. As far as vented products go, i've seen more people soot up their houses with them thinking they can close the damper down to try to keep more heat in.

I am not trying to be argumentative. I have been known to change my thoughts on subjects by getting other points-of-view. I appreciate you reading & responding to my email. I do hope you do as much business as you can possibly handle.


Jimmy Kinney
Southern Home & Hearth, Inc.
Huntsville, Alabama

Sweepy Hello Again Jimmy,
The letters on our letters page are just that: letters from people who choose to send them. Aside from cleaning up a few grammatical errors and some strong language (this is a family website), we publish them just as received, on a page clearly labeled LETTERS FROM VENT-FREE GAS FIREPLACE OWNERS. Would you accuse the New York Times of being crazy, reckless or laughable because they don't require "scientific-based proof" for the claims presented on their letters page? Of course not. And let's try the shoe on the other foot for a moment: where is the "scientific-based proof" for the statements you make in your letters?

How about applying a little common sense to the situation: do you really think over 100 people took the time to write E-mails so they could lie about the problems they're having with their vent-frees? C'mon.

Your inference that we don't like vent-free fireplaces because we don't sell them is exactly backwards: the fact is, we could sell vent-frees any time we wanted to: we don't sell them because we don't like them, as explained right here on our website.

Finally, in all the years we have hosted these vent-free letters pages, nobody has ever tried to claim that vent-frees are "beneficial." Cheaper, yes. Easier to install, yes. If you're going to try to claim that sharing your breathing space with a vent-free is good for you from a health standpoint, we are going to challenge you to provide some of that "scientific-based proof" you talk about.


#12: Vent-Frees Legal in Wisconsin (if you have a leaky house)
Date: Wednesday, October 14, 2009

I like your website. I'm remodelling my living room. I live in Wisconsin and found out that vent free gas logs are legal in the state provided that your house was built before 1980. I guess this is to make sure the house is less efficient so moisture won't build up so fast and the ventilation is leakier (?) than the newer homes. The fireplace company told me to check with local building inspector. He said that my township has no problem with it as long as the state laws are met. I don't know what I'm going to do, but vent free is quite a bit cheaper.


Sweepy Hi Jim,
Don't you find it just a bit unsettling that the state of Wisconsin determines the advisability of your family sharing their living space with a vent-free based upon the age of your house? What if your builder was ahead of his time, insulation-wise? What if some interim owner tightened the place up a bit? Look very carefully at the price you might eventually pay before deciding vent-free is cheaper.


#13: Believes in Direct Vent, but points out Vent-Free is cheaper.
Date: July 14th, 2010

I really like your site and heaters. I believe in the direct vent system, but would like to make one point. Your page on complaints on vent free heaters neglects to point out the reason people buy vent free to begin with and that is cost! I can get a vent free heater on a pedestal for $1500.00. Your vented heaters run $4K until that great descrepancey is changed the prices alone will keep vent free in business.


Sweepy Hi Steve,
Direct vents and vent-frees both come in a range of sizes, styles and prices (we carry several Direct Vent models that sell for less than half of the $4K you mention), but by and large, you have a point. Because there's no vent kit needed, vent-frees are generally cheaper to buy and easier to install. This point is mentioned several times on our vent-free complaint letter page, as well as this page and others in our vent-free section.

We just hope that price-conscious shoppers who might be considering vent-frees will also consider the additional "price" they might pay over the years in the form of potential health problems, mold & mildew damage and soot cleanup.


#14: Believes in Direct Vent for modern house, but thinks Vent-Free is OK for 100 year old Florida leaker..
Date: August 9th, 2010

Hi there :)

I've been in the building business for roughly 35 years, specializing in restorations. I've designed and built a few super insulated homes in my time that used pennies on the typical heating dollar. But at this particular time, I own and live in a well over 100 yo home in North Florida that is as drafty and uninsulated as one might expect for a home of such an age. Of course it was built before central heating. indoor plumbing A/C, electricity or fiberglass. It has two chimneys and 6 fireplaces, both of which are unlined and unsafe to use for wood burning.

In North Florida, we have a distinct winter, typically not serious like in the northern tier states, but a winter none the less. Its got down to the 10 degree range several times while I have lived here as an example. The house is drafty, the gas central air/heat unit which dates from the 60's is very inefficient by modern standards and given the construction for the house would be difficult to replace.

I installed 4- 10,000 btu and 2-30,000 btu ventless units after having the chimneys plugged and fireproofed. I use them for my primary heat source, I rarely if ever turn any but one of them to the max setting, have had very little to nothing in the way of sooting issues. Those that do are easily cleaned up with a mild TSP solution, have had zero CO related issues and collectively they have cut the gas bill by half.

In a tighter, modern construction house such a heater would not be my choice, I'd use a direct vent with sealed combustion air intake and exhaust. But for my current application, they have fit the bill beautifully and I am very happy with them. If anyone has a similar home that is amply drafty by virtue of its age and construction, I wouldn't hesitate to use them.

Regards, Gary

Sweepy Hi Gary,
Thanks for the input! We're certain that, given the vast and untapped potential marketplace consisting of leaky 100 year old Florida houses, the Vent Free Gas Products Association will take your testimonial right to the bank.


Read about how much CO2 a vent-free fireplace exhausts into the breathing space

Read about a recent study of the effects of long-term exposure to CO gases

Read about respiratory irritation from vent-free exhaust in the breathing space

Read a posting about vent-free gas appliances from an indoor air quality scientist

Read what Consumer Reports Magazine has to say about vent-free products

Read our opinion about vent-free gas appliances

Read about a 2016 ASHRAE standard that could eliminate the entire vent-free product category in the US

Have a vent-free experience you'd like to report?  Here's a link to the Consumer Product Safety Commission website.


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