Why Is My Log Burner Smoking?

Is the wood wet?

This is the most common cause. HETAS says wet wood wastes heat boiling off moisture and produces more smoke. Burn wood at 20% moisture or less, and check it with a moisture meter if you're not sure. See firewood moisture content.

Is the fire running too cool?

Burnright says that, apart from when you light or refuel, smoke shouldn't come from the top of the chimney. If it does, West Northamptonshire Council says there isn't enough air getting into the stove: open the controls up and let the fire build. Black glass is another sign the wood isn't burning hot enough.

Is the stove overloaded, or are the logs too big?

Burnright says an overloaded stove produces large amounts of smoke, and oversized logs do the same. Add a few logs at a time, about 125 mm (5 inches) across.

Did smoke come out when you opened the door?

HETAS says to open the door a crack first, so the air pressure can settle, then open it slowly to refuel. Morsø adds that smoke on refuelling happens most when the stove is burning very low, and that leaving the door open for long chills the flue.

Is the chimney cold or drawing poorly?

A chimney draws much better when it's hot, so a fire lit in a cold flue can puff smoke back at first. Lighting from the top down warms the flue faster. Morsø lists other causes of poor draw: a chimney that is too short, poorly insulated or leaky, a sheltered chimney top, or mild weather outside. Those need a HETAS installer or sweep to look at.

Is the chimney blocked?

HETAS lists smoke coming back into the room as a sign your chimney needs sweeping. Soot, tar and birds' nests can all block a flue. See how often to sweep your chimney.

Is something pulling air out of the room?

A stove needs a steady supply of air. An extractor fan in the kitchen or bathroom can pull air out of the house and draw smoke back down the chimney. Turn the fan off and open a window to see if the smoking stops.

When should I stop and get help?

HETAS says there should not be smoke or products of combustion coming into your room, and Charnwood's manuals say persistent fumes are potentially dangerous and must not be tolerated. If smoke keeps coming into the room, let the fire go out, ventilate the room and call a HETAS registered installer or a chimney sweep. A carbon monoxide alarm in the same room is essential.