Why solid fuel appliances need their own carbon monoxide plan

An open fire or wood burning stove is one of the great pleasures of a British home, and for many households it is a genuine source of heat rather than decoration. But solid fuel burns differently from gas, and the risks are different too. Carbon monoxide is colourless, odourless and tasteless, so a room can be filling with it while the fire still looks perfect. You cannot smell it, see it, or judge it by the colour of the flame. Every home with a solid fuel appliance needs an audible carbon monoxide alarm, fitted properly and tested regularly.

What actually causes carbon monoxide in a solid fuel home

Carbon monoxide is produced when fuel doesn't burn completely. In a solid fuel appliance that usually comes down to one of a handful of causes:

• A blocked or partly blocked flue — soot, tar, bird nests or debris blown down by a storm.
• Burning wet or unseasoned wood, which burns coolly and produces more tar and soot, narrowing the flue over time.
• Slumbering the stove overnight with the air controls shut right down, so the fire smoulders instead of burning.
• Not enough ventilation — blocked air bricks, sealed vents and heavy draught-proofing starve the appliance of air.
• Burning the wrong fuel, such as household rubbish, treated timber or coal in a wood-only stove.
• A cracked firebrick, a perished door seal or a flue that has never been swept properly.

A fire that draws well and burns hot is far less likely to produce carbon monoxide, so most prevention is really good burning and good maintenance.

Choose an audible alarm, not a patch

Fit an alarm that meets BS EN 50291 and is marked as suitable for solid fuel appliances. That means an audible alarm with a loud sounder — around 85 decibels at three metres, enough to wake most people from sleep.

Colour-changing patches and cardboard detector cards are not a substitute. They give no warning while you sleep or while you are in another room, and they have a shelf life. If you have one on the kitchen wall, treat it as decoration and buy a proper alarm.

Sealed long-life battery models last the life of the unit; mains-powered alarms with battery back-up are a good option if you are fitting several. A digital display showing peak levels can help you spot a slow rise before it becomes dangerous. Keep smoke alarms as well — a carbon monoxide alarm will not warn you about a chimney fire.

Where to position it

Fit the alarm in the same room as the appliance, one to three metres away from it. On a ceiling, keep it at least 300mm from any wall. On a wall, mount it at least 150mm below the ceiling and roughly at breathing height. Avoid placing it so close to the stove that lighting-up puff-back sets it off.

Avoid corners where air sits still, and keep alarms away from windows, doors and extractor fans, which can carry carbon monoxide away before it reaches the sensor. Don't hide one behind curtains or furniture.

Then think beyond the fireplace. Fit an alarm in every bedroom and in any room a flue passes through or above. If your stove sits directly below a bedroom, an alarm upstairs is worth having. Interlinked alarms, where one sounds them all, are the belt-and-braces option.

Make testing a weekly habit

Press the test button once a week and listen for a clear, loud sound. Vacuum the vents gently every month or so to keep dust out of the sensor. If your alarm takes replaceable batteries, change them once a year — and never borrow them for the television remote.

Every alarm has an end-of-life date, usually five to ten years after manufacture. Write the date you fitted it on the casing so you can see when it is due. Sensors lose sensitivity with age, and an old alarm can quietly stop doing its job.

Pair the alarm with proper maintenance. Have your chimney swept at least once a year, twice if you burn bituminous coal, and always before the heating season. Burn dry, seasoned wood with a moisture content below 20 per cent, check it with a moisture meter if you are unsure, and don't slumber the stove overnight. Keep air bricks and vents clear.

If the alarm sounds, act first and investigate later

Open windows and doors, turn the appliance off if you can do so safely, and get everyone outside — pets included. Do not go back in to look for the cause.

Carbon monoxide poisoning can feel like flu: headache, dizziness, tiredness, nausea, breathlessness or confusion. Symptoms that ease when you leave the house and return when you come back are a strong clue. If anyone is unwell, call the emergency services and tell them you suspect carbon monoxide, and seek medical advice even if symptoms seem mild.

Do not relight the appliance until it has been inspected by a qualified technician, and do not simply press the silence button and carry on with your evening. Once the fault has been dealt with, reset or replace the alarm as the instructions advise, and settle back into that weekly test.