When to Close Fireplace Damper

When to Close Fireplace Damper

Your fireplace damper must be open when you have a fire in your fireplace. It provides the necessary updraft for the smoke and prevents carbon monoxide poisoning. But when should you shut or close the wood-burning fireplace damper?

Not sure how to open or close fireplace damper? See damper instructions here.

Close Fireplace Damper In Warm Weather.

During the seasons you will not be burning wood in your fireplace, close the damper. An open damper is much like an open window or open door – interior air you are paying to air condition will be wasted and escape out any opening.

Open door and open damper - both let air conditioned air out

In the summer, an open fireplace damper is like an open door. Both let air conditioned air out of the home.

Close Fireplace Damper When Fire Is Completely Out.

During the part of the year you are using your wood-burning fireplace, open the damper before you light the fire. If necessary to keep the fire burning well and smoke-free, you may adjust the damper into a semi-open position.

Shut the damper when the fire is completely, absolutely out. That means ashes are cool to the touch even when stirred. If you close the damper before that, you risk carbon monoxide poisoning.

Functionally, this is what that means:

  • Start your fire before you “need” it.
  • Toward the end of the evening, let the fire die down instead of adding more logs.
  • Separate remaining bits of firewood on the grate. Stir embers on the fireplace floor.
  • Leave the damper open overnight. Yes, you will lose some heat up the flue, but you will save the occupants of the home from poisoning by colorless, odorless carbon monoxide.
  • In the morning, stir the embers and check them for any hot spots. Only when they are completely cold to the touch is it safe to shut the fireplace damper.

Close the Fireplace Damper in Preparation for a Hurricane or Heavy Rains.

See Hurricane Fireplace Tips to see more about why you should close the fireplace damper with you are expecting heavy rains.

Is the Fireplace Damper Open or Closed?

To close a throat damper in a fireplace, lift the handle and pull it back towards you.

To remember whether your damper is open or closed (and to remember to close fireplace damper when the embers are completely cooled), you can use a brass damper hook with a Closed and Open side or a brass fireplace sign with a Closed and Open side.


 NOTE: For Fireplaces with Installed Gas Logs

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.
  • Even if your pilot light is not lit, there is the danger that someone might forget to open the damper when using the gas fireplace. Gas fireplaces emit a copious amount of carbon monoxide, so they must always have an open vent.

If your fireplace damper is stuck in either the closed or open position, here’s how to un-stick it.



Susan shares ways to make homes, especially those with fireplaces, renewing spaces for families. When not writing for FireplaceMall.com, she can often be found by a fireplace with a book in hand.

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5 comments on “When to Close Fireplace Damper
  1. Ron says:

    I feel like I should know this but I want to make sure
    since its been so long since I’ve used my very old (28yrs) gas fireplace i just wanted to be sure
    what the correct steps to lighting the fireplace are ?
    the fireplace is gas and has logs inside and a gas key to turn on the gas however it does not have a pilot or ignition system like my newer home fireplace does ( that pilot is on all the time and has an on off wall switch)
    thank you for your help

    • Tom says:

      Ron, one of that vintage should be check for safety by a certified gas appliance technician before it is used. He or she can give you instructions on the correct steps for lighting for the model you have. Enjoy your fireplace.

  2. my sister leaves her chimney flue open all the time so she can smoke up the chimney. She ran out of heat twice now this winter. Now she claims she doesn’t have enough money for the heat! Leaving the flue open is the same as having money sucked out of the chimney! I told her she needs to remember to keep her flue closed. she said, “Yeah I should be better about that.” ?? What? Leaving it open is o.k. sometimes? haha.

  3. Jerry Fleming says:

    I have a gas log fireplace. Should I close the damper when the fire is burning in order to disseminate the heat into the room?

    • Tom says:

      Jerry, leave the damper open whenever the fire is burning so exhaust gases can escape through the chimney instead of entering your room.

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