Why is my fireplace not drawing, and what should you check first?

First, handle the smoke

If smoke is already in the room, act first and diagnose later:

1. Open a window or door to clear the air
2. Do not add more fuel
3. Let the fire die down, and do not pour water on a hot firebox
4. Keep everyone, including pets, away from the smoke

If a carbon monoxide alarm goes off, leave the house and call 911. If you see flames outside the firebox, smell smoke in other rooms or hear a roar in the chimney, leave and call 911. Do not go on the roof.

A fire that smokes the room once while the house was windy is a clue, not a crisis. A fireplace that smokes every time is telling you something is wrong, and it should not be used again until you know what.

How a chimney draws, in plain terms

Warm air is lighter than cold air, so it rises. In a chimney, the hot gases from the fire rise up the flue and pull fresh air in from the room. That pull is called draft. It depends on three things working together: a flue that is warm, a clear path from bottom to top, and enough air coming into the house to replace what goes out.

When any of those fails, the system reverses. Cold air falls down the flue, smoke spills out of the opening, and the fire sulks. Taller flues generally draw better than short ones, and a flue sized wrongly for the opening can behave poorly even when it is clean.

The causes below are listed roughly from the easiest to check to the hardest.

A useful habit is to keep a short log. Write the date, the outdoor temperature, whether it was windy, which fans were running and how the fire behaved. After two or three entries, patterns show up that save the technician time and make the diagnosis more accurate.

Easy causes you can rule out

• Damper not fully open. Check the handle or lever. A damper that is stuck, rusted or bent may not open all the way.
• Cold flue. A flue in an exterior wall can be full of cold air that sits like a plug. Start with a small, hot kindling fire so the flue warms up before you add logs. Do this only when no smoke is entering the room.
• Wet or green wood. Damp wood smolders and makes more smoke than heat. Read our note on firewood choices in New England.
• A fire that is too big or too small. A tiny fire does not heat the flue. A very large one can overwhelm the opening.
• Glass doors or screens closed too early. Leave them open until the fire is established, unless the manufacturer says otherwise.
• Ashes piled too high. A deep ash bed can choke the air feeding the fire. Remove cold ashes, and leave a thin layer, using a metal container kept outside the house.
• Room too cold. A closed-off, unheated room can pull cold air into the flue. Opening the door to a warmer part of the house can help.

Is the house short of air?

Modern, tight homes can run low on air. Kitchen and bath fans, a clothes dryer, a range hood and a furnace all pull air out. If there is no easy way for fresh air to come in, the fireplace loses the contest and the chimney can be pulled in reverse.

Try this simple test on a day when the problem occurs. Turn off all exhaust fans and the dryer. Crack a window near the fireplace about an inch. Then light a small fire and see if the draft improves.

• If it does, the house is starved for air, and the fix is usually a fresh air source rather than chimney work
• If it does not, the problem is likely in the chimney or the fireplace itself

Note whether the problem happens at startup only, on windy days, in warm weather or after a night when the fireplace was not used. Those details help narrow the cause and are useful to give the technician.

Blockages and deposits

A clear flue needs to be, well, clear. These are the usual things that get in the way:

• A bird or squirrel nest, or leaves and debris that fell in an uncapped flue
• Soot and creosote buildup that narrows the flue
• A collapsed or loose flue tile or a piece of fallen brick
• A damaged liner or a cap with clogged mesh
• A smoke shelf or smoke chamber packed with debris

You may see signs: a bit of daylight at the damper, a bad smell, debris on the firebox floor or smoke that has become worse over time. A chimney sweep with inspection costs $299 fixed and clears loose deposits so the flue can be assessed. If animals are the cause, removal runs $299 to $900. Heavy creosote buildup is priced by stage, from $299 to $450 for stage 1, $450 to $700 for stage 2 and from $700 for stage 3.

When the chimney or the fireplace is the cause

Sometimes a clean, open flue still will not draw. Then the design or condition of the system is the issue. A technician will check how the parts relate to each other.

• Flue size versus opening size. A fireplace opening that is too large for the flue spills smoke. Sometimes a smaller opening or a lowered lintel solves it.
• Chimney height. A short chimney, or one close to a taller roof, tree or neighboring building, may suffer from downdrafts in wind.
• Smoke chamber shape. A rough or poorly shaped chamber disturbs the airflow. Smoke chamber repair is $500 to $1,500.
• Damper. A warped damper may need repair or replacement, $199 to $1,200.
• Liner. A cracked or oversized liner can hurt draft. Repair is $1,200 to $2,500, replacement $1,500 to $4,500.
• Cap. A clogged or wrongly fitted cap restricts the exit. A standard cap is $300 to $700.

For the full process, see the chimney inspection page. Our smoke chamber repair page covers one of the less obvious causes.

Do not change the fireplace before you know the cause

It is tempting to buy a new insert, a draft inducer or a taller pipe right away. Please do not. A new part on the wrong problem can cost money and leave you with the same smoke. The right sequence is simple:

1. Stop using the fireplace if it smokes the room
2. Rule out the easy causes above
3. Have the flue inspected, with a camera when needed
4. Approve a repair that matches what is found

You should receive photos of the problem and a written price before work starts. The $49 inspection is credited toward approved repair work. To book, call (617) 404-9587 or use the form at /contact/.

Questions homeowners ask