CO Alarm FAQs

There is no legal requirement to test your CO detector, however, it is recommended that you test your device using the test button on a weekly basis. To make sure that it is still operating correctly and it does not need the batteries replacing (on the models with replaceable batteries). There is also a test gas that simulates real CO that you can use to test your alarm.

This would likely indicate that the CO alarm has come to the end of its life, usually approx. 7 years, depending on the unit. If the CO alarm is not as old as this, this would likely indicate a fault with the unit. In the case of the unit still being within its warranty period, we would recommend that you take it back to where you purchased it from for replacement. If you purchased it from us, we will be happy to replace it for you. Please contact our Customer Service department on 0800 612 6537 for assistance.

Yes they do, there are variations between the different makes and models but most will chirp approx. every 30 seconds. If you have a CO alarm with a digital display this may show ERR or END. There should also be a replace by date on the back of the alarm. It is important to purchase a replacement alarm as soon as possible to ensure you have warning should there be carbon monoxide in your property.

Depending on where your property is located in the country, as there are different laws you will need to adhere to when installing a system of alarms for your home or rental property. There are a few manufacturers that have an interlinked CO alarm that can be added to your mains or radio interlinked system.

Yes, one carbon monoxide alarm is required in any room used as living accommodation which contains a fixed combustion appliance (excluding gas cookers). Where a new or replacement combustion appliance is installed, the CO alarm must be powered by a sealed lifetime battery or directly wired into the mains electrical supply.

The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 applies to all social housing and rental properties in England and Wales and requires working smoke and carbon monoxide (CO) alarms are installed. Specifically for carbon monoxide detectors, this 2022 update expanded existing requirements from just solid fuel burning appliances to include all fuel types. Landlords are required to ensure alarms are present, installed in an effective way to protect occupants, and in working condition at the start of each tenancy. Occupants are responsible for regular testing of alarms and replacing batteries, where applicable, but replacing a faulty or end-of-life alarm is the landlord's responsibility. The rules in Approved Document J must also be followed when a new or replacement combustion appliance is installed, just like for owner-occupied homes.

Please see our page on carbon monoxide alarm legislation for more specific guidance or view our range of suitable carbon monoxide alarms.

Yes, carbon monoxide alarms are required where a new or replacement fixed combustion appliance is installed.

Owner-occupied homes in England and Wales should follow The Building Regulations Approved Document J for combustion appliances and fuel storage systems. Requirement J3 states that, where a new or replacement fixed combustion appliance is provided, appropriate provision shall be made to detect and give warning of the release of carbon monoxide. Government guidance recommends the use of 'tamper-proof' or 'sealed for life' alarms such as those using lithium batteries, or alternatively mains-powered models which are directly wired into the mains electrical supply as opposed to plug-in types.

Please see our page on carbon monoxide alarm legislation for more specific guidance or view our range of suitable carbon monoxide alarms.

In most cases you do not need a CO2 detector or alarm system in your home. Though it is poisonous at higher concentrations, carbon dioxide is generally not produced in significant amounts by typical household activities – even gas appliances and open fires do not create levels of any real danger. The most likely scenario where it would be advisable is home-brewing in which CO2 cylinders are used. Some larger fish tanks and aquariums can employ the use of carbon dioxide too. If any of these describe your home then a CO2 monitoring and alarm system is highly recommended.

Yes, carbon monoxide alarms are required in homes with fuel-burning appliances. From February 2022, all homes in Scotland – both owner-occupied and rented – must be brought up to a certain minimum standard of smoke alarms and CO alarms. This legislation specifies a common minimum coverage; it does not take precedence over Building Regulations or other specific legislation that may stipulate more alarms are required.

In terms of carbon monoxide specifically, alarms are required in all rooms where there is an appliance of any fuel type (e.g. fireplace, boiler), excluding those solely for cooking, or a flue. All types of alarm must be mains powered (fixed wiring, not a mains plug) or powered by a tamper-proof lifetime battery.

Please see our page on carbon monoxide alarm legislation for more specific guidance or view our ranges of suitable carbon monoxide alarms.

Yes, a sealed battery or mains-powered carbon monoxide alarm must be provided with a new or replacement combustion appliance, excluding those designed solely for cooking purposes. The CO detector should be installed in the same room as the appliance if it is a room normally used by occupants; if it is, for example, a boiler located in a dedicated room / cupboard that occupants do not normally enter, the detector should be located just outside of that cupboard or room.

This has been in effect since 2012, with the guidance in clause 2.51 of The Building Regulations Technical Booklet L setting out requirements for combustion appliances and fuel storage systems.

Please see our page on carbon monoxide alarm legislation for more specific guidance or view our range of suitable carbon monoxide alarms.

Yes, landlords are required to provide CO alarms for their tenants.

Section 8 of The Private Tenancies Act (Northern Ireland) 2022 requires landlords to provide and keep in proper working order 'sufficient appliances' for detecting and giving warning about dangerous levels of carbon monoxide. The original legislation does not specify the power type, quantity, or positioning of alarms, so new legislation effective from September 2024, The Smoke, Heat and Carbon Monoxide Alarms for Private Tenancies Regulations (Northern Ireland) 2024, is being introduced to clarify these aspects. For carbon monoxide requirements in rented properties, the law now specifies that a carbon monoxide alarm should be mains powered (not plugged in) OR powered by sealed batteries that last the full sensor lifespan. The alarms should be fitted in every room which contains a fixed combustion appliance or flue, excluding cooking appliances.

Please see our page on carbon monoxide alarm legislation for more specific guidance or view our range of carbon monoxide alarms.

In short: yes, but there isn't just one, single rule to follow.

Legislative requirements for carbon monoxide alarms vary by which country of the UK your house is in and whether it is rented or owner-occupied. Most legislation requires at least one carbon monoxide alarm is fitted near new or replacement fuel-burning appliances (e.g. boiler, oven, fire place), specifically either 'tamper-proof' / 'sealed for life' alarms such as those using lithium batteries, or alternatively mains-powered models which are directly wired into mains supply as opposed to plug-in types. Some countries have exceptions for fuel-burning appliances used solely for cooking. Rented properties mostly require a CO alarm immediately even if no appliances are being installed or replaced.

Please see our page on carbon monoxide alarm legislation for more specific guidance, links to relevant legislation & government guidance, and links to carbon monoxide alarms suitable for each. Alternatively, please view our full range of carbon monoxide alarms if you already know what type you need.

Yes this is possible. It is advisable to check the user instructions for your specific CO alarm for instructions. Generally, the way to zero the peak level is to push the test/reset button while the peak level button is depressed to clear the memory. Always check the user manual for specific instructions for your CO alarm.

All CO detectors purchased through Safelincs are tested to BS EN 50291-1, ensuring a quality product with a manufacturers warranty. It is important that as a landlord you also make sure that you have the correct type of carbon monoxide installed in your property depending on the country that your rental property is in.

Yes, we sell a range of combined smoke and CO alarms which detect both fire and carbon monoxide.

We also sell combined heat and CO alarms which detect changes in temperature in a room rather than smoke. These are ideal for kitchens & garages where smoke or dust may often be present.

Safelincs has signed up to Valpak's WEEE (Waste Electrical and Electronic Equipment) Distributor Take-Back Scheme*. This means if you are a Safelincs customer you can take old smoke, heat and CO alarms to your local recycling centre.

To find your nearest recycling centre, please visit www.recycle-more.co.uk. Find out more about smoke alarm disposal.

*Registration ID: 7370

Carbon monoxide (CO), also known as The Silent Killer, is created by the incomplete combustion of fossil fuels (gas, oil, coal and wood) used in everyday appliances such as heaters, engines and boilers. CO is undetectable by humans as it is a colourless, odourless and tasteless toxic gas, hence why it is important to have carbon monoxide detectors where incomplete combustion is possible. Humans can experience carbon monoxide poisoning with prolonged exposure to CO, and may experience symptoms ranging from headaches and nausea to coma and death.

There is no legal or BSI requirement to test CO detectors with a test gas. It is usually sufficient to check your CO detector is working by using the test button on the detector. For peace of mind sign up to our free reminder service.

Different levels of carbon monoxide (CO) affect the body in different ways. Exposure to large amounts of CO can cause sudden death, and prolonged exposure to low levels of carbon monoxide can have adverse effects on the body and brain.

This table shows the effects of different levels of exposure to carbon monoxide.

See our carbon monoxide information page for more details.

CO detectors should be installed near potential sources of carbon monoxide, essentially any fuel-burning appliances. As you are likely to be most affected by CO in areas of your home that you spend the most time in it is advisable to install alarms in those areas as well, such as at head height in the living room and bedrooms. If your property has an attached garage with a connecting door through to the house, it is recommended to fit a CO alarm inside the house leading from that doorway.

Carbon monoxide has been proven to spread into neighbouring properties through open windows, as well as through loft spaces in semi-detached or terrace houses.

Battery powered carbon monoxide alarms can typically be installed wall-mounted or left free-standing on flat, level surface. Combined smoke & CO alarms or mains-powered CO alarms are typically installed on the ceiling.

• Near an appliance: they should be placed within 1 to 3 metres horizontally from the appliance and between the height of the appliance to 150mm below the ceiling – i.e., not above a stove where it would be in the path of steam or fumes.
• In living spaces: they should be positioned close to where the occupant's head is likely to be most of the time – e.g., on your bedside table.
• On the ceiling: at least 30cm away from any wall, light fitting, or other obstruction.

Do not install CO alarms within 3 metres of doors or windows, above radiators, or immediately close to anything that gives off steam or fumes like a cooker or shower room. Similarly, it is not recommended to install detectors in dusty areas such as workshops or garages.

For more information, please check the manufacturer's instructions – you can download the PDF manual from the relevant product page on our site.

CO detectors should be installed near potential sources of carbon monoxide, essentially any fuel-burning appliances such as boilers, cookers and ovens, fireplaces (both open and enclosed burners), and portable generators. As you are likely to be most affected by CO in areas of your home that you spend the most time in it is advisable to install alarms in those areas as well, such as the living room and bedrooms. It is also worth noting that while one detector is better than no detectors at all, larger homes may require several detectors to cover the property fully.

Also note that carbon monoxide has been proven to spread into neighbouring properties through open windows and, in semi-detached or terrace houses, through loft spaces. If your property has an attached garage with a connecting door through to the house, it is recommended to fit a CO alarm inside the house leading from that doorway.

Battery powered carbon monoxide alarms can typically be installed wall-mounted or left free-standing on flat, level surface.

• Near an appliance: they should be placed within 1 to 3 metres horizontally from the appliance and between the height of the appliance to 150mm below the ceiling – i.e., not above a stove where it would be in the path of steam or fumes.
• In living spaces: they should be positioned close to where the occupant's head is likely to be most of the time – e.g., on your bedside table.

Combined smoke & CO alarms or mains-powered CO alarms are typically installed on the ceiling and should be at least 30cm away from any wall, light fitting, or other obstruction.

Do not install CO alarms within 3 metres of doors or windows, above radiators, or immediately close to anything that gives off steam or fumes like a cooker or shower room. Similarly, it is not recommended to install detectors in dusty areas such as workshops or garages.

For more information, please check the manufacturer's instructions – you can download the PDF manual from the relevant product page on our site. You can also watch our video guide to positioning CO detectors.

The symptoms of CO poisoning can range from mild flu-like symptoms such as headache, drowsiness, confusion, nausea and dizziness to more severe symptoms like breathing difficulties and irregular heartbeat. CO poisoning can ultimately lead to coma and death.

View more symptoms on our carbon monoxide information page.

No, normal smoke alarms cannot detect carbon monoxide (CO). Only combined smoke and CO alarms can detect both fire and carbon monoxide gas.

Since February 2022 all homes in Scotland must be fitted with interlinking smoke and heat alarms. In addition carbon monoxide alarms are required if there is a carbon-fuelled appliance or flue. 
View our list of alarms suitable for the Scottish regulations.

Most legislation advises at least one carbon monoxide alarm is fitted near new or replacement fuel-burning appliances that are fixed installations, though rented properties (both social and private sector) often require CO alarms be provided by landlords even if no appliances are being installed or replaced. Examples include boilers, coal fires, wood burners, and gas ovens and cookers, though an exception is often made in legislation for gas appliances solely used for cooking.

However, any and all materials can give off CO when burning, including gas cookers. Carbon monoxide can also spread from neighbouring properties or outside sources such as vehicle fumes. Because of this, Safelincs strongly recommends the installation of carbon monoxide detectors in every home, and also at head-height in bedrooms to protect occupants while sleeping.

Landlords, please see our pages for English, Welsh, and Scottish alarms or our landlord guidance page for more information.

Carbon monoxide (CO) is a colourless, odourless, tasteless gas that is undetectable by humans. Inhaling CO reduces the blood's ability to carry oxygen to the body's organs and cells.

Each year, over 50 people die in the UK from exposure to carbon monoxide. Many more people die through strokes and respiratory illnesses made worse by inhaling low levels of CO over prolonged periods.

To protect you and your family, purchase a carbon monoxide detector and use the test button weekly to check it is in working order.