How long can you leave a gas fireplace on? Leaving a gas fireplace running too long can increase the risk of fire or dangerous fumes. The length of time a gas fireplace can be left on depends on the type of gas fireplace you have. Some types can be left on continuously, while others should only be operated for a few hours at a time. For more information on types of gas fireplaces and how to use them safely, see below.

How Long Can You Leave a Gas Fireplace On?

If you have a fully vented gas fireplace with a sealed glass front, your fireplace can be operated continuously — the same way your furnace works, said service representatives from three different home heating installation companies in New York and Colorado. However, if your gas fireplace is vent-free or has doors on the front that can easily be opened, you should only operate it for two to three hours at a time, the service representatives said. Below, we’ve listed types of gas fireplaces and safety considerations when operating a gas fireplace.

Types of Gas Fireplaces

There are three types of gas fireplaces most commonly found in homes:

  • Fireplace inserts: This type of gas fireplace can be installed in an existing, traditional wood-burning fireplace. Fireplace inserts have a vent pipe that is placed inside the existing chimney to release exhaust. Most fireplace inserts can be run continuously, as long as the glass front is sealed.
  • Direct vent: With a direct vent gas fireplace, the vent for the exhaust is placed through an exterior wall of your home, so it can be installed in houses that don’t have existing fireplaces or chimneys. Most direct vent gas fireplaces can be run continuously, as long as the glass front is sealed.
  • Vent-free: A vent-free gas fireplace is designed to operate similarly to an oven, providing a secondary heat source that is not vented. Because vent-free gas fireplaces don’t vent exhaust fumes outside the home, they should only be operated for a few hours at a time.

Safety Considerations for Gas Fireplaces

Many people worry about toxic fumes with any kind of gas-burning appliance. In particular, carbon monoxide is a concern. Although gas fireplaces are generally safe and don’t emit toxic levels of carbon monoxide, it’s a good idea to have a carbon monoxide detector installed in any room where you have a gas fireplace — particularly if you have a vent-free model.

To prevent the risk of fire, all furniture and loose objects, such as curtains or drapes, should be kept at least three feet away from gas fireplaces. Additionally, the glass front of a gas fireplace can get very hot during operation, so it’s important to keep small children and pets from touching the fireplace.

In Summary

Most vented gas fireplaces with sealed glass fronts can be operated continuously. However, vent-free gas fireplaces should only be run for a few hours at a time to prevent potential exhaust buildup in your home. For more information on home heating, see our articles: Are Infrared Heaters Worth It? and Where to Buy Coal Near Me? and Can I Run My Gas Fireplace Without the Fan? Answered.


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