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InsightHorizon Digest

Do I have to open the flue for my gas fireplace

Author

Andrew Mccoy

Updated on April 04, 2026

As a general rule, if you have a gas log fireplace, you should never close your flue when in operation. If the fireplace is not operating, but the pilot light is lit, you should not close your flue.

Can I keep flue closed with gas fireplace?

As a general rule, if you have a gas log fireplace, you should never close your flue when in operation. If the fireplace is not operating, but the pilot light is lit, you should not close your flue.

What happens if you don't open the flue?

Close it when it’s not it use. Operating the fireplace with the damper partially closed will not generate more heat. Instead, blocking the passage through the flue will result in smoke entering the home. The damper should be kept open until all embers are finished burning to prevent smoke from escaping into the home.

Do you have to have the flue open on a gas fireplace?

“Fully Vented” gas logs must be burned in a fireplace that is capable of burning real wood and must be burned with the damper open. The reason for this is that they do not burn the gas cleanly and create exhaust that is very similar to burning a real wood fire. This exhaust needs to be able to go up the chimney.

Should I leave my fireplace flue open?

A fireplace damper should always be kept open while the fire is burning. Furthermore, keep the damper open until all the embers are done burning. … By leaving the damper open, heat is being lost as warm air is being pulled through a hole in your living room (the chimney) all the way up and through the roof.

Is a damper and flue the same thing?

A damper is located in the flue of your chimney. The flue is where the smoke escapes when the fire is going. Dampers are placed inside of the flue to help control ventilation. Your damper should have a chain or handle that you can access in order to open and close it.

Can you get carbon monoxide poisoning from a gas fireplace?

Yes, gas fireplaces are one potential cause of carbon monoxide poisoning. … An improperly maintained or ventilated gas fireplace can create incomplete combustion, creating carbon monoxide, and causing this toxic gas to linger—putting those inside at risk of carbon monoxide poisoning.

Can you close the glass doors on a gas fireplace?

Can the glass doors on my fireplace be closed when my gas logs are burning? No.You must leave the doors open when you are operating RealWood Elite gas logs to avoid damaging the controls.

Do all fireplaces have a flue?

Technically, a flue is any open vertical space in a chimney that allows smoke to escape the home from the firebox. But because every chimney’s flue must be lined, a chimney liner is usually referred to as the flue, as well. Every wood-burning or gas fireplace has a flue.

How do I know if my gas fireplace is vented?

Turn on the fireplace. If the flames reach above the gas logs and the look like a wood burning fireplace, then the logs must be vented. If the flames are small, an have a blue cast, the fireplace is vent-free.

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Can I leave the flue open overnight?

The smoke from burning wood contains carbon monoxide, so in order to prevent this toxic byproduct from entering your home, it is important to leave the flue open overnight. This enables a draft to carry the compound out into the atmosphere, instead of sinking down the chimney and saturating the room.

Can you keep a gas fireplace on all night?

The short answer is this: gas fireplaces that are fully vented and have safely and properly sealed glass fronts are fine to be left alone to run continuously.

How is a gas fireplace vented?

In a direct vent gas appliance, fresh air is drawn from the outdoors into the hearth unit, and expelled air is sent outside via a flue system that terminates outside. Most direct vent gas fireplaces are vented to the outdoors horizontally (through the wall), but they can also be routed vertically (through the roof).

Can you close the damper when pilot is on gas fireplace?

If you have installed gas logs in your fireplace, the damper should never be closed. If you have a pilot light constantly burning under your gas logs, shutting the damper puts you, your family and your pets at severe risk of carbon monoxide poisoning.

Should you open a window when you have a fire in the fireplace?

Open a window when using the fireplace to prevent the room from becoming smoky. … The window needs to be open only a few inches. You can check to make sure the smoke will go up the chimney properly by lighting a match, quickly blowing it out and watching the smoke to see whether it’s going up and out.

Is it OK to leave the pilot light on in a gas fireplace?

We recommend that you turn off your gas fireplace pilot light seasonally. Turning off your gas fireplace’s pilot light can save a substantial amount of energy and money. It is important to remember that not all gas fireplaces have “standing” pilot light, or, a pilot light that is “always on”.

Do you have to open the damper with gas logs?

One caution, though: Fireplaces with installed gas logs are required to have the damper open at all times. That’s either because a pilot light is constantly burning under the logs or because the homeowner might forget to open the damper when he or she turns on the fire. … Those gases contain carbon monoxide.

Can you use a fireplace without a damper?

Does My Chimney Have a Fireplace Damper? … And while older wood-burning fireplaces can function safely without a damper (gas fireplaces cannot), a chimney without a damper is just a gaping hole in the roof of your house. It’s a gateway for frigid air to enter and for heated air to escape in the winter.

How can you tell if the flue is open?

Lean in under your chimney just outside of your wood burning stove. You should find a metal device just within the chimney or flue opening. The damper is open if you can see through the damper up to your chimney. If you only see a metal plate, the damper is in a closed position.

What is the lever on the side of a fireplace for?

Also, some wood burning fireplaces have a lever to open or close the outside air vent to the fireplace. If your fireplace has this lever (usually located on the left inside panel) make sure the outside air vent is in the open (or up) position. The outside air kit is designed to provide additional air for combustion.

Does a gas fireplace need a chimney liner?

Homeowners with gas or electric inserts most likely do not need a new liner because those types of fuel don’t produce enough heat to damage a masonry chimney.

What is the purpose of glass doors on a gas fireplace?

Fireplace glass doors increase fire heat – When closed during a burning fire, Fireplace glass doors can more than triple the net heat realized in your home. (Doors should be open when burning a moderate to large fire or when burning gas logs.)

Does the glass on a gas fireplace get hot?

“While gas fireplaces, stoves and inserts are a great asset to any home, the glass can become very hot during operation and stay hot long afterwards, creating a potential burn hazard,” said Jack Goldman, president & CEO of HPBA.

Are my gas logs vented or unvented?

All gas log inserts are considered Natural Vented appliances.

What is the difference between a vented and unvented gas fireplace?

Vented and Ventless Gas Logs are a little different. Vented gas logs burn like a real wood fire with a yellow flame that produces smoke. … Ventless (vent-free) gas logs burn cleanly with a lower flame that does not smoke. You can burn them with the damper closed to heat your room.

How do you vent a gas fireplace without a chimney?

If you don’t have a chimney, a natural vent system can also use a pipe venting system, which is typically installed through the roof. Here, you can get around having to use a brick and mortar chimney to rid the home of fumes and use a pipe system instead.

Is it safe to sleep with a fire in the fireplace?

You should never go to sleep while a fire is in the fireplace. It may seem safe—after all, the fire is small and controlled behind a metal grate.

How long do fireplace ashes stay hot?

Hot coals, hidden in a pile of ashes and thus well insulated, can stay hot for up to four days because the ash acts as an insulator that keeps the coals from burning out.

How do I know if my damper is open or closed?

Before lighting a fire, you can tell if the damper is open by placing your hand into the fireplace. If you feel a draft coming down the chimney, it is a good indicator that the damper is open. If you don’t feel any cold air coming down the chimney, it means that the damper is closed.

Should I turn off the pilot light on my gas fireplace in the summer?

Your Utility Bill Perhaps the most important reason to turn off gas fireplace pilot light in summer is because of the money and energy you will be saving. If you leave the pilot light on during the summer it is simply sitting there burning gas, which is wasting gas and contributing to an exorbitant energy bill.

Is it cheaper to run a gas fireplace or the furnace?

Is it cheaper to run a gas fireplace or a furnace? … A modern furnace is more efficient in turning gas into heat than a gas fireplace. This means that although a furnace costs more to run per hour than a gas fireplace, it turns more of that energy into heat and can warm a whole house rather than a single room.