What to do if my Carbon Monoxide alarm goes off?

CO detectors, or carbon monoxide alarms, are essential for the detection of a deadly gas, carbon monoxide (CO). This gas cannot be seen, tasted or smelt and is only detected with the use of co detectors. It is produced through the incomplete combustion of fuel, such as gas, wood, coal and oil. If your carbon monoxide alarm is going off, do not assume it is a false alarm.

What to do when your carbon monoxide alarm is going off

You should assume that there is CO present and should follow these steps to ensure your safety.

  • Stay calm, open doors and windows to increase ventilation
  • Where safe to do so, turn off any fuel-burning appliance
  • Leave the premises and notify other occupants of the potential carbon monoxide leak (you should also notify any occupant of premises adjoined to your home as CO can seep through walls and floors
  • Call Gas Emergency Services 0800 111 999 or a local Gas Safe Registered Engineer to check for the source of carbon monoxide
  • Get medical help for anyone suffering from symptoms of CO poisoning

Symptoms of carbon monoxide poisoning

The main symptoms of carbon monoxide poisoning are:

Carbon monoxide poisoning symptoms: persistent headaches

Persistent Headaches

Having persistent dull headaches and tension type headaches.

Carbon monoxide poisoning symptoms: dizziness

Dizziness

Having waves of dizziness or feeling light headed and off balance.

Carbon monoxide poisoning symptoms: nausea/vomiting

Nausea / Vomiting

Feeling like you need to be sick (nausea) and actually being sick (vomiting).

Carbon monoxide poisoning symptoms: stomach pains

Stomach Pains

Pains in your stomach or lower abdomen, sometimes accompanied by diarrhoea.

Carbon monoxide poisoning symptoms: difficulty breathing

Difficulty Breathing

Sudden shortness of breath or difficulty breathing (dyspnoea).

Carbon monoxide poisoning symptoms: tiredness

Tiredness

Having no energy or feeling tired, sleepy, lethargic and sluggish.

Carbon monoxide poisoning symptoms: sudden collapse

Sudden Collapse

Sudden collapse, seizures or loss of consciousness.

Carbon monoxide poisoning symptoms: confusion

Confusion

Confusion, difficulty concentrating and becoming easily irritated.

What causes CO detector false alarms?

A false alarm is when your CO detector alarms and where no carbon monoxide is detected by your engineer. There could be several reasons for this, which can often be easily resolved:

Cause of alarmWhat to do
The carbon monoxide detected did not come from your own appliances but may have seeped through the walls or floor from a neighbour.Check if your neighbours have fuel-burning appliances that might emit carbon monoxide. Carbon monoxide might escape from chimney stacks allowing the toxic gas to enter your premises via a joint loft space.
The replace-by date may have been exceeded.Most CO alarms are only effective for 5-10 years. Once expired, they can sound erratically, or not sound when they should, The expiry date for each unit can be found on the information sticker on the back of the unit.
Excessive moisture from a bathroom may set off your CO alarm.CO alarms can be corrupted by steam, and therefore shouldn’t be installed in bathrooms. If your CO alarm is repeatedly triggered by steam, it may become ineffective, and should be replaced.
Lead acid battery chargers produce hydrogen gas which sets off CO detectors.If you are charging your caravan or boat battery at home, this could set off your CO alarm. Once you have made sure that the alarm is false, it is safe to ignore the alarm in this scenario, but remain vigilant for other signs. If this happens often, invest in a CO alarm with a digital display to assess the level of risk when the alarm sounds.
Freshly screeded floors emit a gas that sets off carbon monoxide alarms.If your floors have just been screeded, and you have made sure that the alarm is false, it is safe to ignore the alarm in this scenario, but remain vigilant for other signs.
The carbon monoxide alarm that you have installed may not be suitable for the type of premisesFor example if it is installed in a caravan, tent, boat or living quarters of a horsebox you will need to ensure that your alarm is Kitemarked to BS EN50291-2. Alarms tested to BS EN50291-1 are only for use in home environments and are not suitable for camping and caravanning.
Smoking indoorsA heavy smoker in a poorly ventilated room the CO from smoking may trigger an alarm. It is recommended to open a window if possible to improve ventilation. If this happens often, invest in a CO alarm with a digital display to assess the level of risk when the alarm sounds.
Homes that are adjacent to very busy roads may experience higher levels of CO in the home when windows are open as traffic fumes may enter the room and set your alarm off.If this causes persistent false alarms, invest in a digital CO alarm, allowing you to see a live CO reading. You can then determine the level of risk. For example, if the reading is high, there is probably a leak. However, if it has just tipped over the threshold due to air pollution, the alarm can be ignored/silenced without having to get an engineer in to check for a leak.
The sound that your alarm is making may not be the alarm sound to alert you that there are dangerous levels of CO present.Most alarms have several audible sounds to indicate things such as low battery warning or that there is a fault with the alarm. Keep the manual safe so that you can refer to it should the alarm go off.

Buying a CO detector

You should have a carbon monoxide detector in every room where there is a solid fuel burning appliance. Only chose CO detectors that have met the rigorous testing standards of the European standard EN50291. These alarms provide peace of mind that this vital alarm has been manufactured and tested to the highest standards. Moreover, investing in a CO detector with a digital display also provides peace of mind, as it allows you to assess the situation when an alarm goes off. This is particularly useful if you have had persistent false alarms due to pollution, smoking, or other external factors, as it allows you to check the reading to assess the level of risk before calling an engineer to check for a leak.

For more information about taking a carbon monoxide detector on holiday, read our blog on this ultimate travel essential, and what to do if you detect a leak.

Kidde Carbon Monoxide Alarm - 7DCO / 7DCOC
Kidde Carbon Monoxide Alarm - 7DCO / 7DCOC
  • Product Life: 10 years
  • Battery: replaceable AA alkaline batteries included
  • Warranty: 10 year warranty
  • Displays CO levels from 10ppm
  • Peak Level Memory - recalls highest CO levels
  • Ideal for domestic use and camping, caravans & boats
  • Kitemarked to BS EN50291-1 and BS EN50291-2
  • Also suitable for the 2022 Welsh legislation
£15.21 ex VAT
£18.25 inc VAT
Buy Now

If you are unsure if you have the correct carbon monoxide alarm installed our customer care team are here to help. You can call them on 0800 612 6537 or email support@safelincs.co.uk.

Angie Dewick-Eisele

Director

Angie Dewick-Eisele is co-founder of Safelincs Ltd, one of the leading fire safety providers in the UK. Angie was Marketing Manager for many years and as Director is these days responsible for Content Management.

Why is my smoke alarm beeping?

Is your smoke alarm beeping in the night and keeping you awake, or disturbing your day? Whether you have mains powered, interlinked smoke alarms, or battery powered smoke alarms, follow our guidance below to troubleshoot the beeping.

What sound is your smoke alarm making?

Smoke alarm sounding continuously

  • First check there is no smoke or fire in your property
  • Make sure the beeping is definitely coming from your smoke alarm. Other alarms in the property such as a carbon monoxide alarm or burglar alarm could be responsible for the noise.
  • Clean the alarm if it is dusty or dirty. Vacuum around the alarm or use a hairdryer to blow out dust on a cool setting.
Replace by date on the back of a smoke alarm | smoke alarm chirping in the night
Replace by date on back of smoke alarm
  • Check the replace by or manufacture date on your alarm. Smoke alarms usually last for a maximum of 10 years, so if the manufacturing date is approaching 10 years or more than 10 years, it’s time to get a new smoke alarm. Sensors inside the alarm deteriorate after this time causing the alarm to be less effective.
  • Check the position of your alarm. There are different types of smoke alarm suitable for specific locations in your home. Find out more below about positioning your alarm.
  • Your smoke alarm may be damaged or have developed a fault. Exposure to water, fire, grease and certain types of paint can cause a fault to develop. If there is a fault, replace your smoke alarm immediately to protect your home and family.

Smoke alarm chirping intermittently

  • Replace the battery* in your smoke alarm. Ensure you are using the correct battery type and are inserting it the correct way around. If the battery is low, it is more likely to sound at night as a drop in room temperature can impact the battery’s ability to power the alarm.
  • Check the manufacture date on your alarm. Smoke alarms usually last for a maximum of 10 years, so if the manufacturing date is approaching 10 years or more than 10 years, it’s time to get a new smoke alarm. Sensors inside the alarm deteriorate after this time causing the alarm to be less effective.
  • Your smoke alarm may be damaged or have developed a fault. Exposure to water, fire, grease and certain types of paint can cause a fault to develop. If you suspect a fault, replace your smoke alarm immediately to protect your home and family.

How to stop wired alarm chirping intermittently

* All new or recently extended homes should have mains powered, interlinked alarms fitted which also have a back-up battery. Intermittent chirping in mains-powered alarms is often caused by low power in the back-up battery.

Replacement batteries for smoke alarms

Smoke alarms usually require either Alkaline AA batteries, an Alkaline 9V battery or a Lithium 9V battery. Buy replacement smoke alarm batteries as soon as possible to ensure that your family would be alerted to a fire in your home.

Mains powered smoke alarm need replacing?

Whether your smoke alarms are mains powered or battery powered, they should be replaced after 10 years due to a deterioration of the sensors. Battery alarms are easily changed and installed, but how do you replace a mains powered alarm? Most mains powered alarms can be replaced without the need for an electrician if you purchase the exact same model, if still available, or an Easichange® replacement where applicable.

Discontinued smoke alarm need replacing?

If you need to purchase a replacement alarm, but find that your existing model has been discontinued, we have a dedicated collection of replacement smoke and heat alarms. This range consists of models specifically chosen to be the simplest, most direct replacement alarms that can often be installed without the need for an electrician.

Related help guides:

Preventing false alarms

The type of sensor an alarm has determines where it should be positioned in the home. False alarms may be due to the wrong alarm type being used in or near a steamy, dusty or smoky environment.

  • Heat alarms are more suited to areas such as the kitchen or garage that are often smoky or dusty. Other types of sensors would be prone to false alarms in these areas.
  • Optical smoke alarms are ideal for bedrooms, living rooms and ground floor hallways.

To avoid causing false alarms or affecting the performance of an alarm, it is good practice to avoid installing alarms in the following locations:

  • Next to a door, window, air vent or fan that would create a draft
  • Outside
  • Anywhere that airflow would be obstructed by curtains or furniture
  • Locations that are steamy or humid such as a shower room

Find out more about positioning your smoke alarm in your home or take a look at our help guides for more information about types of alarm sensor.

Always ensure you act as quickly as possible to change or replace a defective smoke alarm to keep your home and family safe. If you require any further assistance, contact our customer service team on 0800 612 6537 or email support@safelincs.co.uk.

Mel Saunders

Head of Marketing

Mel joined Safelincs in 2020 and leads the content and marketing team.