Vent Free Appliances (Risks, Considerations, and Operating Tips)

This is a less than 5 minute video by industry expert Jerry Isenhour about vent free appliances. Join us as he explains the insights and the positive and negative sides of:

Vent Free Logs

Vent Free Appliances and Vent Free Logs

If you’re thinking of converting an old fireplace in a gas unit, you’re not alone. As a popular option today, a lot of consumers today want to put a gas product in their fireplace. This could be because they dislike burning wood, want ease of use, or prefer the look. Whatever the reason is, we’re here today to primarily talk about Vent Free Logs and Appliances.

There are three main choices when it comes to adding a gas appliance into your home. They are:

  1. Vent Free Gas Appliance 
  2. Venting Gas Appliance
  3. Direct Vent Gas

Personally I feel direct vent gas fireplace inserts are the best investment you make for your home today. For years we’ve been offering regency fireplace products that you can find and can be at many fireplace companies around the country.

But today we are talking about Vent Free Gas Appliances (Vent Free Logs). They are popular units but they are also controversial and come with a host of potential risks.

Check the regulations.

Direct free units are restricted in many areas of the country. They are banned in the entire state of California as well as cities and counties across the US.

Vent free or ventless equipment is a very controversial topic in the chimney and fireplace industry. There are many varying opinions on its use. When considering if vent free is a viable option for your family and lifestyle I consider you read the manufacturer’s guidelines. Determine if it stacks up favorably for your investment and safety. I’m going to say personally that I am no longer a fan of vent free fireplace units or gas logs. I have stopped servicing, selling, or installing them. We currently only sell and install vented gas log sets and direct vent fireplace inserts.

We’re going to supply 2 links to vent-free code maps that may want to consider before investing in a vent free appliance. Check out these map links from and Hansen Wholesale to determine if vent free is even an option in your own county or state.

For health and safety purposes we have these regulations. However, if you operate a vent free unit with care and consciousness, you can potentially safely operate a vent free unit without problem. Take a moment to read the information below to help you operate your vent free appliance safely and efficiently.

What Is a Vent Free Gas Appliance

When we’re talking about vent free we’re talking about logs and gas units that do not do require a chimney to vent out of the home. A vent free gas appliance is an appliance that doesn’t require venting to the outside. These units have been particularly popular in the southeastern United States, but many counties no longer allow the sale of these units.

When we have a vent-free or unvented gas product, what you’re doing is using room air. The room air goes into the firebox – goes into the combustion process – and all the chemical byproducts in the interior of our home are expelled back into the room.

Now, in truth be told, vent free equipment actually does supply a tremendous amount of heat into the home – but it comes with a cost. In my opinion, I wouldn’t recommend leaving a direct vent operate without following the manufacturer’s written guidelines.

Remember to always follow manufacturer guidelines regarding: opening a window to allow for fresh air, not burning the appliance for more than a couple hours in a 24-hour period, and not operating if you have any respiratory problems.

Extra measures to take with a Vent Free Unit

Just as if you wouldn’t want to operate a car in an unvented mode, and you wouldn’t want to operate your furnace in an unvented mode. This is because you potentially have toxic gases that are produced by the gas appliances during the combustion process.

Open a window!

Most vent free appliance manufacturers require opening a window. You may want to consider not using these types of units if you or family have respiratory issues.

Many manufactures recommend that the vent free appliance is within a room where you can get fresh air as part of the combustion process. Many manufacturers advise opening the window to at least a half an inch. As well as addressing clearances to combustibles such as wood framing and fireplace mantles.

Vent Free Usage

Another thing you need is to be concerned about is the usage level of the appliance. Many manufactures of these appliances suggest these should not be operated over two hours a day within a 24 hour period of your home.


There’s also another byproduct of vent free gas, which is moisture. Any time we combust gas we actually have large moisture buildup in the home that is not able to be vented out. Today’s homes are basically built airtight. We have them very heavily-insulated, so that any moisture produced by a vent free gas appliance will remain in the envelope construction of home. This often leads to various types of moisture issues that must be evaluated for health concerns regarding humidity, mold, and mildew.

General Health Risks

Obviously this picture is an exaggeration. But we all must be seriously aware of the chemicals in our home.


Another word of caution about a vent free appliance, they can possibly cause a stress on the heart. It can also hurt the respiratory system for some individuals. People will report odor issues at times from vent-free appliances. To clarify that, we’re combusting both gas and air in through the appliance. The air in the average home today contains a lot of chemicals. We have cleaners in the homes, household detergents, bleaches, hardwood flooring processes, etc. These different types of chemicals are within our environment.

Remember,  we’re pulling the air from the living space into the home. We’re possibly pulling chemical products such as formaldehyde from the furniture and the carpets. All these things are released back into the home during the combustion process of using vent free equipment.

That New Car Smell!

We all have been in a new home or a new car and smelled what we call the new car smell! Well, actually, what that is is the release of formaldehydes from parts of the interior and upholstery of the car or home. It may smell pleasant to you then, but its really chemical formaldehydes released in the air.

Now, as those formaldehydes airborne go into the burner system of a vent free unit, and they’re combusted, along with animal fur, carpeting, and a wide variety of other indoor pollutants. And they actually transform and create a very toxic, very acrid odor. People will smell a smell associated with rotten eggs. Many people think that they have a gas leak, when its actually coming from the combustion processes of using a vent free unit. Those who sell these appliances often claim its just the burning of the logs, which I’m not sure I agree with.

Remember here are the key things to keep in mind with vent free units:

• Don’t overuse the vent free logs or fireplace for an extended period of time.

• Open a window as suggested by your vent free equipment manufacturer.

• Be sure to read the manufacturer’s installation and use instructions.

We hope this article helps you in the consideration of using or investing in vent free products.

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Clay Lamb

Clay Lamb is a Cincinnati Chimney Sweep contractor and the executive producer of the YouTube channel, podcast, and blog Ask the Chimney Sweep. He is also an award-winning educator and public speaker in the chimney and fireplace industry.….Educational Videos….American Chimney Cincinnati, OH We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.

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