How can I stop cold air from coming down the chimney?

Retta Robinson
by Retta Robinson

We have gas logs in what was once a wood-burning fireplace. We don't use the logs anymore because they seemed to suck the heat out of the entire downstairs. The log installer fixed the damper so that it won't close completely, apparently a safety feature in case you light the logs without opening the damper. Now cold air comes down the chimney and our feet get so-o cold. Any suggestions for sealing up the chimney?

  8 answers
  • 26061930 26061930 on Mar 09, 2019

    My mom put an old pillow into a plastic bag, and stuffed it up the chimney of her wood fireplace. I think this would work for your situation, as well. As long as you don't use the fireplace!!

  • Mogie Mogie on Mar 09, 2019


    Foam insulation helps stop drafts from entering through the fireplace. Cut a piece of thick insulation foam -- the type sold in large sheets for construction projects (that is the stiff type) -- to fit the opening of the fireplace like a pull-out panel. Cover the piece with a decorative fabric that matches the room's decor, securing the fabric with pins on the back side for a visually pleasing way to keep the cold air away.


  • William William on Mar 09, 2019

    If you want to seal the chimney what was the point of having the damper adjusted to not close. People have used foam sheets and made panels to put up the chimney. There are inflatable bags that are suffed up the chimney and blown up. Any way to cover the opening that will fit. If you forget to remove anything and fire up the logs is no different than having a closed damper. Just get the damper fixed to close properly.

    • See 1 previous
    • Sharon Sharon on Feb 16, 2021

      I would ask the guy that left your damper partially open to come back and allow it to close like it was meant too. Never heard this one before and I've had chimneys for 70 years. Then i would custom cut a piece of plywood to fit in the front opening that your could paint decoratively.

  • Vimarhonor Vimarhonor on Mar 09, 2019

    We had two leaky chimneys too. I tried making a wooden cover/ screen but that was ineffective.


    Two other options were studied.


    We looked at the chimney balloons as an option on Amazon but with them costing $50 and needeing to be removed and replaced with fireplace use -we decided to purchase a pull down option that works marvelously. Our roofline was not very steep so our situation for a diy installation was quite wasy.


    https://www.rockfordchimneysupply.com/chimney-dampers/top-sealing-chimney-damper-caps


    The balloons are available in many sizes, you would need measurements to determine your size and cost.


    Fireplace dampers are inefficient due to warping and misalignment from frequent heating and cooling. A bad damper can cost you up to 30% more on your heating bill. Your fireplace damper is releasing your indoor heat and letting in cold outside air! The Chimney Balloon is a inflatable blocker that prevents drafts from a chimney caused by a broken, warped, or missing flue damper. It even works in chimneys that have no damper! The Chimney Balloon stops this heat loss by acting as a chimney blocker to insulate your fireplace and save you money, heat, and comfort.


    https://www.rockfordchimneysupply.com/chimney-balloon.php


    https://www.amazon.com/Chimney-Balloon-Inflatable-Blocker-Medium/dp/B000MIO394

  • Pam Walker Pam Walker on Mar 10, 2019

    MEASURE THE OPENING inside the chimney just above the logs. Cut a large piece of cardboard from a box & with duct tape, tape the cardboard over the hole going up the chimney. It shouldn't be visible from the front when company comes over. Only you will know it's there because it'll be inside the inner edge inside the chimney. We did this for ours too. Cheap & effective.

  • Jud22529229 Jud22529229 on Mar 10, 2019

    We bought 2 pieces of plexiglass to cover the opening that we slide behind the screen when weā€™re not using the fireplace. Not visible and easy to slide in and out.

  • Redcatcec Redcatcec on Dec 17, 2022

    We also used a piece of plexiglass to close off our chimney, it was operational at 1 time but the bricks and mortar part above the roof began to degrade, we had it taken down and the roof patched.

  • Pat Pat on Dec 19, 2022

    We had the same situation as you. Wood to gas and found the fireplace sucked gas like mad. So we changed it to electric. You can shut the vent completely and the fire is pretty and gives out a little heat. Works for us.