HY-C Blog

Top Causes of Indoor Fireplace Smoke

Written by Kyla Pehr | Dec 1, 2025 4:30:00 PM

First, a slight chill in the air. Next, the leaves become a vibrant kaleidoscope of oranges, yellows, and reds. Then before you know it, pumpkin spice is everywhere. Like, everywhere. You’re drowning in it, and there’s no escape.

Happy fall y’all!

For homeowners, the turning of seasons also often represents the turning on of the fireplace. After months of disuse, many look forward to curating that perfectly cozy, Pinterest-worthy living room befitting of all the picturesque fall and winter vibes — completed by, of course, a flame-lit hearth.

But then, tragedy strikes. 

Imagine: you’re cozy on your couch, hot chocolate or apple cider in hand, Disney’s The Nightmare Before Christmas is playing… when you realize smoke has started entering your home.

Suddenly, your carefully tailored environment is tainted by the very thing meant to pull it all together: the fireplace.

Why is this happening? What can you do to stop it? Was it preventable? Is The Nightmare Before Christmas a Halloween movie or a Christmas movie? And while we’re at it, is Die Hard even a Christmas movie? Where does the madness end?

Hopefully, this quick-and-easy guide can help answer your burning questions.

The fireplace questions, that is. Sorry, holiday movie fundamentalists; you’re on your own.

Why is my fireplace smoking?

If your fireplace is pushing smoke back into your home, it could be caused by a few different things.

Your damper is closed (or not fully open) 

Is your flue open? If yes, carry on. If no — or if you’re unsure what a flue even is — please stick around.

If you’re not familiar with chimney anatomy (like most real, human people), the flue is the vertical passage responsible for carrying smoke safely outdoors. Really, it’s that simple.

Chimneys have dampers on both ends of the flue:

  • Throat damper (lower end): This is usually closed during summer. It typically has a knob you turn clockwise or a rod you push upward to open.
  • Cap damper (upper end): If this one’s stuck or damaged, it may need replacing. You can replace it yourself, but if roofs, ladders, or heights aren’t your thing, we recommend calling a pro.

Yes, chimney sweeps are real. No, they are not just the stuff of British folklore.

Too much air coming in at once

Your chimney can only handle so much airflow.

Think of it like pouring water into a hole: dump in 10 gallons and it pools at the top, overwhelming the opening. Pour gradually, and it drains smoothly.

Smoke works the same way.

If too much air is coming in too quickly, some will go up the flue, but not all of it. If you limit how much air rushes into the fireplace, smoke moves upward through the chimney more gradually and escapes more efficiently.

Temperature differences are messing with your draft

You know the old saying — “cold air sinks and warm air rises!”

If it’s cold outside (say, 30°F), warm indoor air rises up the flue and pushes through the cold outside air. This creates a convection current, AKA a draft.

If it’s warmer outside (around 50°F) and closer to your indoor temperature, the draft won’t be as strong. Less circulation means smoke lingers.

It’s typically recommended to wait until the weather gets colder to light a fire. The smaller the temperature difference between inside and outside, the greater the chance of smoke lingering in your living room.

Negative air pressure in your home

Homes can develop air-pressure imbalances that mess with chimney draft.

  • Newer homes: often sealed too tightly, limiting airflow.
  • Older homes: often leak air too freely.

Plus, vents — bathroom fans, dryer vents, foundation vents, soffit vents — all push air out. If too many run at once, they create low pressure, pulling air down the chimney instead of letting smoke rise.

These situations are not uncommon, so they’re worth keeping in mind.

Something’s Living (or Stuck) in Your Chimney

Maybe there’s a blockage in your chimney; a bird’s nest, a raccoon, another critter squatting in your flue.

Maybe your chimney is dirty; creosote accumulates, and it can clog your chimney. Creosote accumulates, narrows the passage, and — fun fact — is the number one cause of house fires in the U.S.

A clean chimney helps smoke escape upward instead of re-entering your home.

Your firewood is wet

Wet wood won’t light. Wet wood just smokes.

Don’t put wet wood in your fireplace. 

Make sure your firewood is properly seasoned, or dried naturally. Maybe consider using a log rack to keep it elevated off the ground and allow air to circulate around it fully, spurring evaporation. 

What should I do next?

More immediately, if your fireplace is currently smoking into your home:

  • Turn your fireplace off (if gas or electric).
  • Extinguish your fire (if wood-burning).
  • Make sure your damper is fully open.
  • Turn your fans on.
  • Open your windows.

Smoke, like water, spreads through every gap. If there’s a way in, smoke will find it.

That said, keep in mind that this is a preventable issue. There are further steps you can take to safeguard your home from smelling like a campfire — which objectively isn't a bad smell, but it definitely gets old after a while. And smoke stays for a while.

A Solid Fix: Liberty Foundry Co.™ Fireplace SmokeGuards™

SmokeGuards reduce the size of your fireplace opening, limiting how much air rushes into the firebox and easing pressure on the chimney system. With this slower, controlled airflow, the flue can draft properly, helping prevent smoke from spilling into the room.

They’re especially helpful for the “too much air, too fast” problem.

This spring-loaded tool is easy to install; to get started, all you need is a tape measure and a Phillips-head screwdriver. Measure your firebox opening, insert the centering parts, apply the silicone caulk on top (provided), and you’re done.

It comes in three heights — 4”, 6”, and 8” — to ensure a proper fit for firebox openings between 28-½” and 48”. The black powder coat offers a sleek, modern finish, too.

Other helpful tips…

SmokeGuards might beat costly masonry retrofits, but there are other steps you can take depending on the cause:

  • Wait until it’s cold enough outside to light a fire. Some sources recommend 40°F, though that recommendation varies.
  • Make sure your chimney is clean and open. Try using the SootEater® Drill Powered Rotary Chimney Cleaning Kit.
  • Warm your flue before starting a fire: light a small piece of newspaper and hold it near the damper to help start the draft.
  • Double check that your firewood is properly seasoned.

And don’t skip a professional chimney sweep. Their inspection and cleaning can prevent problems long before you notice anything’s wrong.