Carbon Monoxide Detector London — Alarm Installation & CO Safety

Carbon monoxide detectors should be installed: (1) In every room that contains a fixed combustion appliance — boiler room, room with a gas fire, or room with a wood-burning stove. (2) In bedrooms adjacent to rooms with combustion appliances, or where a boiler cupboard shares a wall. (3) At breathing height — approximately 1–1.5 metres from the floor, or at the manufacturer's specified height. Do NOT place CO alarms: directly above or beside a gas appliance (normal trace CO during ignition can cause false alarms); in garages (exhaust fumes will trigger alarms repeatedly); in areas of high humidity such as bathrooms (moisture damages sensors). In a typical London terraced house with a combi boiler in a kitchen cupboard, a single detector at breathing height in the kitchen is the minimum — a second in the main bedroom is best practice.

Yes. Since 1 October 2022, under the Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022, landlords in England must install a carbon monoxide alarm in every room used as living accommodation that contains a fixed combustion appliance (excluding gas cookers). This covers: rooms with gas boilers, gas fires, wood-burning stoves and oil boilers. The alarm must be in working order at the start of each tenancy. Landlords must repair or replace a faulty alarm as soon as reasonably practicable after being informed. Local councils can impose a fine of up to £5,000 for non-compliance. The regulations also require smoke alarms on every floor.

Carbon monoxide poisoning is often called the 'silent killer' because CO is colourless and odourless — you cannot detect it without an alarm. Symptoms of CO poisoning are frequently mistaken for flu or food poisoning: headache (the most common early symptom); dizziness and nausea; shortness of breath; confusion and disorientation; chest pain; and in severe cases, loss of consciousness. Key distinguishing signs: symptoms improve when you leave the property and return when you go back in; multiple people in the household (including pets) experience symptoms at the same time; symptoms do not include a fever (unlike real flu). If you suspect CO poisoning: leave the property immediately, get fresh air, call 999, and do not return until the emergency services have confirmed it is safe.

In London properties, the most common sources of dangerous carbon monoxide are: (1) A poorly serviced or faulty boiler — incomplete combustion produces CO instead of CO₂. This is why annual Gas Safe servicing is critical. (2) A blocked or damaged flue — if the flue that vents combustion gases outside is blocked (by a bird's nest, frost damage, or structural movement), CO spills back into the property. (3) A gas fire that hasn't been serviced — particularly older gas fires that burn in open fireplaces with deteriorating seals. (4) A wood-burning stove with a blocked or downdrafting chimney. (5) Running a vehicle or petrol generator in an attached garage. London's older housing stock — Victorian terraces and converted properties — has higher rates of blocked and deteriorating flues than newer builds.

If your CO alarm sounds: (1) Leave the property immediately — do not waste time collecting belongings. (2) Leave the door open as you go to help ventilate. (3) Call 999 once outside — the fire brigade responds to CO emergencies and carries detection equipment. (4) Do not re-enter the property until the emergency services confirm it is safe. (5) Once cleared, call a Gas Safe registered engineer to inspect and service all combustion appliances before using them again. A CO alarm sounding is a genuine emergency — do not assume it is a false alarm without investigation. If any household members are showing symptoms (headache, nausea, confusion), seek medical attention immediately.

Most carbon monoxide detectors have a sensor lifespan of 5–7 years, after which the electrochemical sensor degrades and the device must be replaced (not just have its batteries changed). Check the manufacture date on the back of your alarm — this tells you when it was made, not installed. Replace it 5–7 years from the manufacture date, or whenever the alarm displays an 'end of life' warning (a steady beep or blinking light pattern distinct from the CO alert). Battery replacement extends the power but NOT the sensor life. Mains-powered alarms with battery backup still need sensor replacement on the same schedule. We check CO alarm condition as part of every annual boiler service.