Energy Vanguard Blog

A Ventless Gas Fireplace Is a Liability

Posted by Allison Bailes on Wed, Jan 16, 2013

ventless vent free gas log fireplace combustion safety indoor air quality iaq frontFirst of all, let's call it what it really is. The industry likes the term 'vent-free' when talking about gas fireplaces that keep all the exhaust gases in your home. I prefer the term 'ventless' or, even better, 'unvented.' Not a huge deal, but the ventless gas industry wants you to feel that you're being liberated of a burden by not having an exhaust vent. I think it's important for people to know that they're actually missing something important when they go with a ventless gas appliance.

Second, unvented gas fireplaces are a liability. I wouldn't have one in my house and advise those who do have one either to remove it, replace it, or just not use it. Yes, I know that some people love them and have never had a problem with theirs. Those people have commented in some of my articles criticizing these appliances. I also know, however, that plenty of people with unvented gas fireplaces complain of headaches and other problems.

Before we get into the fun stuff, let me address the question of how to determine if your gas fireplace is vented or not, just in case. The answer is quite simple. You put your head into the fireplace (remember to turn it off first!) and look up. If there's a hole, it's vented. In the photo below, all I saw was a steel plate with no hole.

ventless gas log fireplace combustion safety indoor air quality iaq top vent free

An article that just won't quit

I've written about combustion safety here in the Energy Vanguard Blog a number of times and will continue to do so because it's such an important part of building science and home performance. The most popular article of all over the past 6 months has been Bob Vila and the Vent-Free Gas Fireplace — A Sorry State of Affairs, which I wrote over a year ago. Lately it's been getting 200-300 views every day.

Why is this article so popular? I think it's because a lot of people are looking to understand the issues. More than a few are feeling ill when they use unvented fireplaces, and they want to confirm their suspicions. These things are in a lot of houses now, andventless unvented vent free gas fireplace can make you sick people are buying those homes without knowing of the problems.

Occasionally, people insist on getting the unvented gas fireplace. Todd Vendituoli, a contractor/blogger in Vermont/Bahamas, commented in the Bob Vila article that he lost a job because the client wouldn't hear of a vented model. Years later, Todd ran into them and they told him "that the fireplace was a mistake and had taken it out."

You can read the full article by clicking the link above, but let me repeat the main reasons that ventless gas fireplaces are bad:

  • Even when working perfectly, they put a lot of water vapor into the house. (See my article on how combustion of natural gas works.)
  • Drafts, fans, candles, and tight houses can mess up the combustion process.
  • Many homeowners don't understand how to operate or maintain them.

If you read the articles I linked to and the comments, you'll see that there's a very good reason that you won't find people who understand building science recommending these things.

Meet Perry Bumpers

Yesterday I got an email from Perry Bumpers. His company, Fireplace Creations by BMC, sells gas fireplaces in Tennessee, and I linked to his website in my Bob Vila article. I didn't know him then and have never communicated with him until he wrote to me yesterday. I linked to his site because he refuses to sell unvented gas fireplaces and proclaims so publicly on his website.

He reached out to me to tell me that every year in the heating season, they get a lot of complaints from people who have ventless gas fireplaces in their homes. They want to find out if it's really true that these appliances could be the cause of their health problems and what they can do about it. At the time he wrote, he said he had a man in his showroom whose wife sent him there to "get the correct information about their ventfree logs they have in there home. She had told him go to BMC and get the facts, that she was not crazy that the logs were making her head hurt and making her sick."

direct vent gas log fireplaceBumpers wrote that they've done about 40 estimates to replace ventless gas fireplaces with direct-vent models so far this season and replaced about 10. The others would like to do it, he told me, but they don't have the money for it yet. The main reasons their customers give for wanting to replace the ventless models are "complaints about bad smell, soot, moisture and health related issues." Because of all that he knows about unvented gas fireplaces and the complaints he hears from people who use them, he wrote, "It’s mind boggling to me vent-free products are still being sold."

It's nice to see companies choose to do the right thing, as Vendituoli and Bumpers do, even if it means losing some business. As Bumpers wrote to me, "We will never stop trying to make sure the consumer has the facts about ventfree products."

I know it's unlikely that these things will go away anytime soon, but the more people find out about these problems, the better. As homeowners doing their research find out the truth and turn away from these ventless gas fireplaces, homes become safer.


Related Articles

Bob Vila and the Vent-Free Gas Fireplace — A Sorry State of Affairs

3 Problems with Atmospheric Combustion Inside the Building Envelope

Unvented Natural Gas Space Heaters Should Be Removed

Fire! — Understanding What's Happening in Your Combustion Appliances


Photo of sick person by akeg from, used under a Creative Commons license.

Tags: HVAC, indoor air quality, moisture problems, health & safety