Carbon Monoxide Alarms & Detectors

CO or carbon monoxide detectors are refined pieces of safety equipment. They use electrochemical sensors which rely on electrodes immersed in a chemical solution that’s sensitive to carbon monoxide. When the electric currents of the chemical solution change as a result of exposure to carbon monoxide, the electrodes detect this and trigger the alarm.

Read our complete guide to carbon monoxide detectors to learn more.

Carbon monoxide is colourless and odourless. You won’t be able to detect it without a carbon monoxide detector. So if your detector goes off, trust it and swiftly take action.

Carbon monoxide detectors, like smoke alarms, emit a loud warning signal once triggered. When you hear carbon monoxide alarm, immediately open all windows and doors to ventilate the area, turn off all gas supplies, and evacuate the area. Once a safe distance away, contact an emergency gas engineer. (Note: if your carbon monoxide detector is emitting intermittent beeps, it means the battery needs to be replaced.)

Common symptoms of CO poisoning are flu-like and include headaches, dizziness, exhaustion, nausea, chest pain and disorientation. Carbon monoxide is fatal, even in low concentrations in the air.

Carbon monoxide is lighter than air and so rises. Carbon monoxide detectors should therefore be placed at head height on a wall. In a room with a boiler, place the detector at the same height as the boiler, but 1 to 3 metres away from it. Avoid placing the detector directly over a fireplace, stove or fire-producing appliance. Ideally, carbon monoxide detectors should be placed on every floor of a home. Make sure children can’t reach or tamper with the detector.

There are portable carbon monoxide detectors which can be fixed to surfaces or left free-standing. They’re a popular choice for homes, caravans and boats. The Kidde Mains Carbon Monoxide Alarm is one we highly recommend – it has a digital display and a peak level memory for when you’re away from home. 

We carry battery-powered and mains-powered carbon monoxide detectors. For the former, you can opt for models which run on standard AA batteries (they come with a ‘low battery’ indicator) or Lithium-ion batteries which last for 7-years.

Our Kidde premium carbon monoxide detector and mains carbon monoxide detector both come with digital displays that are easy to read and provide constant information on CO levels.

All our carbon monoxide detectors are British Kitemarked and compliant with BS EN50291.

In England and Wales, all rented accommodation and holiday homes that are rented out must have a carbon monoxide detector in any room with a carbon-fuelled appliance (such as a boiler, fire, stove or heater).

In Scotland, carbon monoxide detectors with a sealed lithium battery are compulsory in every room with a carbon-fuelled appliance or a flue.

A carbon monoxide detector triggers when it detects CO gas above a safe threshold. Common causes include faulty or poorly ventilated boilers, gas fires, wood burners, and other fuel-burning appliances. Blocked flues or chimneys are a frequent culprit. Some detectors will also sound a low-level alert before concentrations reach a dangerous level, giving you time to ventilate and evacuate.

The most common physical symptoms are unexplained headaches and dizziness, particularly if multiple people in the household experience them at the same time or symptoms improve when you leave the property. On the appliance side, a yellow or orange boiler flame instead of blue, and excessive condensation on windows near gas appliances, can indicate incomplete combustion. A CO detector remains the only reliable way to confirm the presence of the gas.

Some local councils, fire and rescue services, and energy suppliers offer free CO alarms to eligible households, typically those with older residents, low incomes, or properties with solid fuel heating. However, free schemes vary by region and availability can be limited. If you need certified protection now, our detectors start from under £15 and meet BS EN 50291 which is the UK standard recommended by fire services.