Fireplace smoking into the room
A wood fireplace that pushes smoke into the room usually has an airflow problem, not a broken part. The damper may be closed or only partly open, the flue may be too cold to pull, or the house itself may be pulling air down the chimney. Wet wood and fires built too big or too far forward make it worse. If smoke is filling the room right now, deal with that first.
How a fireplace pulls smoke up the chimney
A working chimney pulls because hot gas is lighter than the cool air around it. When the flue is warm, the rising smoke creates a gentle suction at the fireplace opening, called draft. Room air flows into the firebox, feeds the fire and carries the smoke up past the open damper, through the flue and out the top. The damper is a metal plate at the top of the firebox that closes the chimney when you aren't burning. A cap on top keeps out rain, animals and leaves.
Anything that weakens that pull lets smoke roll out of the opening instead. A closed or half-open damper chokes the path. A cold flue holds a column of heavy air that pushes down until it warms up. Exhaust fans, a clothes dryer, a furnace and a tight, well-sealed house can all pull air out faster than it comes in, so the house sucks air down the chimney. Wet wood makes more smoke and less heat. A blockage, like creosote buildup, a nest or a clogged cap screen, narrows the flue. Some fireplaces also have an opening that's large for the chimney, so they smoke a little even when everything else is right.
Why the fireplace smokes
The smoke has nowhere to go but the room.
Heavy cold air in the chimney pushes smoke back down.
Fans, a dryer or a tight house draw air down the chimney.
Smolders and makes lots of smoke with little heat.
Smoke escapes past the top of the opening.
Creosote, a nest, a clogged cap, or a short chimney.
| You notice | Likely cause | Start at |
|---|---|---|
| Smokes right as you light it | Damper not fully open | Step 1 |
| Smokes at first, then clears | Cold flue | Step 2 |
| Worse with fans or dryer running | House pulling air | Step 3 |
| Fire hisses and smolders | Wet wood or poor fire build | Step 4 |
| Worked fine, now suddenly smokes | Blockage in the flue or cap | Step 5 |
| Small puffs at the top of the opening | Draft or opening size problem | Step 6 |
Let's fix it
- Check that the damper is fully openDo this with the fire out and the firebox cool. Find the damper control. It's usually a lever, a handle or a rotary knob just inside the top of the opening. Some chimneys have a top-sealing damper instead, worked by a chain or cable that hangs down in the firebox. Push the lever all the way to open, or pull the chain until it hooks. Then shine a flashlight up. The damper plate should stand open, and you should see a dark, open flue. If the damper only opens part way, or won't move, stop and don't light a fire. A rusted or broken damper is a job for a sweep.
- Warm a cold flue before lightingA cold chimney is full of heavy, cool air that pushes smoke back into the room. This often happens on the first fire of the day, and with chimneys on an outside wall. With the damper open, roll two or three sheets of newspaper into a loose tube. Light the top end and hold it up inside the firebox, over the grate and just under the damper, for about a minute. Keep your hand and sleeve below the flame. You'll feel the air start to pull upward and see the flame lean toward the flue. Drop the paper onto the grate and light the fire right away while the draft is going. If the smoke never lifts, skip to Step 3.
- Stop the house from pulling air downTurn off the kitchen range hood, bathroom fans and the clothes dryer while the fire burns. Then open a window an inch or two in the same room, as close to the fireplace as you can. Light a stick of incense or blow out a match and hold it at the top edge of the opening. Smoke that drifts into the fireplace means good draft. Smoke that drifts into the room means the house is pulling air. If cracking the window fixes it, your home is too tight for the fireplace to get enough air. That's common in newer or recently sealed homes, and it isn't your fault.
- Burn dry wood in a small fire at the backWet or green wood smolders, hisses and makes far more smoke. The EPA advises burning wood with moisture below 20 percent. A firewood moisture meter costs about $20 to $40. Split a log and press the pins into the fresh inside face; readings under 20 are dry enough. Dry wood is usually lighter, with cracked ends and a hollow knock. Store it outside, not in the house. Build a small fire on the grate, pushed toward the back wall of the firebox, with small kindling under a few split pieces. Big fires near the front spill smoke past the top of the opening. Never use gasoline, lighter fluid or trash to get it going.
- Look for a blockage from belowIf the fireplace drew fine before and suddenly smokes, something may be in the flue. With the fire out and the ashes cold, put on safety glasses. Open the damper and shine a bright flashlight up from inside the firebox. Look for leaves, twigs, a nest, fallen bricks, or a thick black crust or shiny glaze on the walls. That crust is creosote, and it can catch fire. A mesh cap screen on top can also clog with soot, which you may see as a dark patch at the top. Don't poke at a nest; some birds are protected. If you see any of this, stop. Don't burn again until a sweep clears it.
- Call a certified sweep for blockages and draftBook a chimney sweep certified by the Chimney Safety Institute of America (CSIA) if you saw a blockage, if the damper is stuck, or if it smokes after Steps 1 to 4. Don't go on the roof yourself. The sweep can clean creosote, remove nests, clear or replace the cap, and check the flue liner. NFPA 211, the national chimney standard, calls for an inspection at least once a year. If the chimney is clean but still smokes a little, ask about draft fixes. A metal smoke guard across the top of the opening, a taller flue, or a different cap can help. Gas fireplaces are a different system, so have a gas fireplace technician check those.
Watch it done
- Smoke rises straight up into the flue from the moment the fire catches
- Incense smoke at the top of the opening drifts into the fireplace
- The fire burns bright with little smoke and no hissing
- The room doesn't smell smoky after the fire
If it comes back
If the smoking returns partway through the season, creosote or soot may be building up, or the cap screen may be clogging. Have the chimney swept, and burn only dry wood so it builds up more slowly.
If it only smokes on cold, windy days or when the furnace runs, the house is pulling air. Keep a window cracked near the fireplace, and see how to stop drafts around windows for sealing the rest of the house without starving the fire.
If your carbon monoxide alarm sounds while the fire burns, get everyone outside, call 911 or the fire department, and read what to do when a carbon monoxide alarm beeps. If a smoke alarm keeps going off from a little fireplace smoke, see the guide for a smoke alarm going off, but don't disable it.
What a pro typically charges (a rough estimate; prices vary by area): A chimney sweep and basic inspection typically costs about $150–$400. A new chimney cap installed often runs about $150–$500, and a smoke guard about $50–$150 for the part.
Find a certified chimney sweep near you