Are Vent Free Appliances Really Safe?

Are Vent Free Appliances Really Safe?

5 Minute Read

What Is A Vent- Free Appliance?

Vent free appliances can also be referred to as "ventless", "non-vented", and "unvented” appliances. Let's briefly look at what a vent free appliance is so that we can gain a better understanding of their safety. A vent free appliance burns natural gas or propane to create a flame for us to see and heat to warm us up. The burner used to create the flame is calibrated to burn the fuel 99.9% efficiently. The bi-products of this high efficient combustion is 99.9% efficient heat, Carbon Dioxide, (the same gas we exhale from our lungs), a small amount of water vapor (who knew fire made water?), and a very minimal amount of bi-products from things in the air such as dust and pet dander. More on these bi-products coming up.

Are They Safe?

Vent free appliances are very safe when installed properly. The appliance must be set up per the manufacturer's instructions. These instructions and guidelines are certified to a number of several national testing agencies like Underwriters Laboratories (UL) and the American National Standards Institute (ANSI). These standards require a device called an oxygen depletion sensor. An oxygen depletion sensor turns the appliance off BEFORE oxygen levels in a room reach a concerning level. Because of the potential for the oxygen level in a room to be lowered even minimally and the bi-products from pet dander and dust, they are not recommended for those who already have breathing issues like asthma or emphysema. The same is true for vented wood burning fireplace and those already having breathing issues.

Where Can I Install A Vent Free Appliance?

Vent free appliances are available as fireplaces for installation into a wood framed cavity, freestanding stoves, gas logs, inserts for existing brick and mortar fireplaces, and wall hung heaters. Because of the nature of their combustion, vent free fireplaces have BTU limitations when installing into a bedroom or bathroom of 10,000 BTU's. The state of California has not allowed the installation of vent free products since the technology was developed over 50 years ago. Because of lower oxygen levels in high altitudes, there are often restrictions to their installation. Always check with your local code authority before installing a vent free appliance.


Vent free fireplaces have been installed in people's homes for over 50 years. They are nationally certified as safe by multiple reputable testing agencies. That being said, not every product is a good fit for every home. They should not be installed into a home where someone has breathing issues. They should not be installed at higher altitudes. Restrictions are in place for bedroom and bathroom installations. When installed properly, they make a great supplemental heat source for a chilly room and are great for warming your home during power outages.

July 27, 2023
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