Why is my fireplace smoking into the room?

The short answer

Smoke comes into the room when the chimney is not drawing properly, meaning the smoke is not being pulled up and out. The usual causes are:

1. A cold flue.
2. A blocked or dirty chimney.
3. Wet or unseasoned wood.
4. Not enough air reaching the fire.
5. Wind at the chimney top.

Most can be fixed. But smoke in the room is also a safety warning, because the fumes include carbon monoxide. If it keeps happening, stop using the fire until the chimney has been checked.

1. A cold flue

Warm air rises, cold air sinks. When a chimney has not been used for a while, it is full of cold air. When you light the fire, that cold column of air resists the warm smoke, which spills out into the room instead.

This is very common in Malta, where many fires are lit only on colder evenings or at weekends, and holiday homes may sit unused for weeks.

What to try:

• Warm the flue first. Open the damper fully, then hold a lit, rolled-up newspaper up towards the flue for a minute or so until you feel the draught pull upwards.
• Start with a small, hot fire of dry kindling before adding logs.
• Avoid lighting a large, smoky fire in a cold chimney.

If the smoking stops once the fire is going, a cold flue was the cause.

2. A blocked or dirty chimney

A chimney can be narrowed or blocked by:

• Soot and creosote from previous fires.
• Bird nests built over the summer, when the chimney is unused.
• Fallen mortar, stones or debris, especially in older chimneys.

Signs: smoke from the moment you light the fire and all the way through, a fire that is hard to keep going, twigs or soot falling into the grate, and a strong smoky smell even when the fire is out.

What to do: stop using the fire and have the chimney swept. Never light a fire to burn out a nest, because it can start a chimney fire. Our guide on how often to sweep a chimney explains why once a year matters.

In chimneys unused since last winter, the blockage is often a nest. See bird nests in chimneys.

3. Wet or unseasoned wood

Wet wood burns cool and makes a lot of smoke, more than the chimney can easily carry. It also leaves creosote that narrows the flue over time.

Signs: logs hiss and steam, the fire is hard to keep going, and there is a lot of white or grey smoke.

What to do: burn only seasoned wood with a moisture content below 20%, and check it with a moisture meter. Damp Maltese winters can make stored wood wet again, so keep it covered and off the ground. See our guide to the best firewood for a wood burner.

4. Not enough air reaching the fire

A fire needs a steady supply of air from the room to replace the air going up the chimney. Modern homes and apartments with well-sealed windows and doors can starve the fire of air, so the chimney pulls air down instead of pushing smoke up.

Things that make it worse:

• Extractor fans in the kitchen or bathroom.
• Tumble dryers venting outside.
• Closed doors between the fire and the rest of the house.
• Another fireplace in the house that is lit or open.

What to try: turn off extractor fans and open a window slightly in the room with the fire. If the smoking stops straight away, an air shortage is the cause. A longer-term fix, such as an air vent near the fire, should be discussed with a sweep or stove installer.

5. Wind at the chimney top

Strong or gusty wind can blow down the chimney, especially when:

• the chimney is shorter than nearby buildings or roof structures, which is common where new floors have been built next door;
• the chimney top has no cowl;
• the wind blows from a particular direction.

Signs: the fire only smokes on windy days, or when the wind is from a certain direction.

What to do: a sweep can advise on a cowl or cap for the chimney top, which can reduce downdraught and also keeps birds out. If a new building next door is now taller than your chimney, ask a specialist whether the chimney needs to be extended.

Shared chimneys in older houses

In older Maltese townhouses and village terraces, chimneys are sometimes shared with a neighbour or run alongside a neighbour’s flue. Problems in one flue, or a neighbour’s fire, can affect how yours draws. A sweep can check how your chimney is built and whether it is connected to anything else.

If the fireplace has not been used for years, see using an old farmhouse fireplace for the first time.

How to work out which cause it is

• Smokes only at first, then fine: cold flue.
• Smokes all the time, from the start: blockage or dirty chimney.
• Hisses and steams, lots of white smoke: wet wood.
• Stops when you open a window: not enough air.
• Only on windy days: wind at the chimney top.

Stay safe

• Fit a carbon monoxide alarm in the room with the fire, and test it regularly.
• If smoke keeps coming into the room, let the fire die down, open windows and do not use it again until the chimney has been checked.
• If you hear a loud roaring from the chimney or see sparks from the top, it may be a chimney fire. Get everyone out and call 112. See our guide to the signs of a chimney fire.

Book a sweep

If the smoking does not stop with the simple fixes above, the chimney needs sweeping and checking. clear.mt arranges chimney sweeping for open fires and wood burners across Malta and Gozo, including older farmhouses in Gozo.