A carbon monoxide alarm that chirps, or sounds, the week the clocks go back.

Why the alarm is the job this week

GOV.UK says the clocks go back one hour at 2am on the last Sunday in October. For 2026 that Sunday was 25 October. The page, last updated 24 November 2025 and read again on 27 October 2026, says the UK is then on Greenwich Mean Time. This note is for the week that follows, when a household presses the test button or hears a chirp it had been sleeping through.

The Home Office Fire Kills campaign says to test smoke alarms at least monthly, whatever the power source, by pressing the button until the alarm sounds. A sound you started, which stops when the test is finished, is that check working. A loud alarm that continues after the test, or that starts when nobody has pressed the button, is the section below.

Carbon monoxide has no colour and no smell. The NHS says fires and appliances that burn gas, wood, oil or coal can produce it if they are badly installed, faulty, or poorly maintained, and that an alarm in each room with one of those appliances is the way to hear it. HSE says an alarm is a useful warning, and that it does not stand in for regular maintenance and safety checks by a Gas Safe registered engineer.

Heating and hot water that both stay off are a different fault: no heating and no hot water the first time you switch the boiler on. A programmer running an hour late after the clock change sits in a radiator that stays cold when the heating comes on. A gauge that falls again after a top-up is a boiler that keeps losing pressure.

A loud alarm you did not start

Leave before you open a list on this site. National Gas says that if the carbon monoxide alarm sounds, or you suspect a leak, you stop using the appliances and switch them off, open doors and windows, and leave straight away. Stay calm, and avoid raising your heart rate. Call 0800 111 999. The same page says to use that number to report a gas or carbon monoxide emergency. The call is free and open 24 hours. Stay out until the emergency services have advised you. Ask for medical help as well. National Gas says fresh air on its own does not treat exposure.

The same National Gas page also names the HSE Gas Safety Advice Line on 0800 300 363. HSE describes that line as information on gas safety, open 9am to 5.30pm Monday to Thursday and 9am to 5pm on Friday, excluding bank holidays. A sounding alarm uses 0800 111 999, including through the night. A British Sign Language user can contact the National Gas Emergency Service through SignLive, which National Gas says is free.

If you can also smell gas, use the gas steps on that page as well. Do not smoke or light a match. Do not turn electrical switches on or off. Turn the meter off at the control handle unless the meter is in the cellar, and do not go into a cellar to reach it.

Northern Ireland uses another gas number. nidirect says that if you smell gas, turn the supply off at the meter, open windows and doors, do not switch electrical equipment on or off, and phone 0800 002 001. The same page says concerns about unsafe gas equipment go to a Gas Safe registered engineer. It describes the smell of gas. It does not set out a separate script for a carbon monoxide alarm.

Symptoms on the NHS page are a headache, dizziness, feeling sick or being sick, feeling weak, tiredness and confusion, chest and muscle pain, shortness of breath, a face that turns hot and red, and loss of vision. They can come and go, and they can ease after you go outside. The NHS says to call NHS 111 if you think you have carbon monoxide poisoning, and to call 999 if breathing is difficult, if someone is suddenly confused, has lost consciousness, feels weak, or has chest or muscle pain. Do not drive to A&E. Scotland, Wales and Northern Ireland may send urgent medical calls through their own services. The emergency gas call still comes before any tradesperson.

Fire Kills says never to disconnect a smoke alarm, or take the batteries out, if it goes off by mistake, unless you are replacing them. A carbon monoxide alarm that is sounding is the leave-and-call path above. If you cannot tell a smoke alarm from a carbon monoxide alarm, leave and call.

A regular chirp, with nobody unwell

A single regular chirp is often the alarm asking for a battery, or telling you the unit has reached the end of its life. The chart is the manual. This page does not translate one brand's pattern into a rule for every box. If the manual is missing, or the noise does not match it, treat it as a sounding alarm and follow the section above.

Where the manual calls the chirp a low battery, fit the battery the manual names. Fire Kills says a smoke alarm that chirps on a regular basis needs a new battery immediately, and that a ten-year sealed battery alarm is replaced as a whole. The low-battery chirp on most smoke alarms can be silenced for a while with the test button, and Fire Kills says the alarm can still sound if it detects smoke. A sealed carbon monoxide alarm that the manual calls end-of-life is a new alarm. Take the old one down when you are putting the new one up, and follow that manual for the test.

Anyone with the symptoms in the section above still uses NHS 111 or 999, and the gas emergency line if a fuel-burning appliance may be involved. A chirp does not cancel those symptoms.

HSE's domestic gas FAQ, read on 27 October 2026, says carbon monoxide alarms cost from £15 and are sold in most hardware shops. The page does not date that £15, and it does not name a shop. It is a starting price for the alarm itself. It is not an electrician's visit, and it is not a quote from this site. HSE says the alarm should comply with British Standard EN 50291 and carry a British or European approval mark, such as a Kitemark, and that you install and maintain it as the manufacturer describes.

A mains-powered alarm that stays silent when you hold the test button, once you are sure it is not giving a carbon monoxide warning, is an electrician. Fire Kills says mains-powered smoke alarms need a qualified electrician to install them. Open the electrical list, including London, Manchester, Birmingham, Leeds and Bristol. NICEIC or NAPIT is printed only when that record already has it. You still ask what the visit covers, and you still phone.

If you rent in England, and the test does nothing

A sounding carbon monoxide alarm is still the emergency line. The landlord comes after you are out and the gas emergency service has been called. This section is for an alarm that fails its test, or that keeps chirping after a battery, while everybody feels well.

The GOV.UK booklet on the Smoke and Carbon Monoxide Alarm (England) Regulations, updated 29 July 2022 and still that page on 27 October 2026, applies to England. From 1 October 2022 a relevant landlord, private or social, has to equip at least one smoke alarm on each storey where there is a room used as living accommodation, and a carbon monoxide alarm in any room used as living accommodation that contains a fixed combustion appliance other than a gas cooker. The booklet says the regulations do not apply to owner-occupiers. They also leave out some tenancies, including a home shared with the landlord, and student halls of residence.

The booklet tells a tenant whose alarm is not working to replace the batteries if they can. If it still does not work, or the batteries cannot be changed, report it to the landlord. Keep a copy of what you sent. Once the landlord is told, and the alarm is found not to be in proper working order, the booklet says the landlord repairs or replaces it as soon as reasonably practicable. The same booklet says a local authority can impose a fine of up to £5,000 where a landlord fails to comply with a remedial notice, and that the fine is per breach. The booklet describes itself as a general guide, and it is dated 29 July 2022. It is the page GOV.UK was showing on the day this note was checked.

A room with only a gas cooker sits outside that carbon monoxide duty. An alarm that sounds in that room is still the emergency path. The NHS list of appliances that can produce carbon monoxide includes gas cookers.

HSE points readers to separate guidance for Scotland and for Wales. This note does not fold those pages into the England duty. Northern Ireland is outside the England regulations as well.

If you own the home

The England landlord regulations do not apply to an owner-occupier. A failed test, or an end-of-life chirp, is yours to put right: a battery where the manual allows one, a new alarm where it is sealed, or an electrician where the alarm is mains-powered.

A new boiler is a different moment. Approved Document J, the 2010 edition incorporating the 2022 amendments, for use in England, says a carbon monoxide alarm should be provided in the room where a new or replacement fixed appliance is installed, for solid fuel, for gas other than an appliance used only for cooking, and for oil. The document says that alarm should meet BS EN 50291-1:2018, with a battery designed to last the working life of the alarm and a warning when that life is ending, or a mains-powered Type A alarm with fixed wiring, not a plug-in type, and a sensor-failure warning. It also says the alarm does not stand in for correct installation and regular servicing. The position and the fitting sequence are in that document and in the manufacturer's instructions. This page does not repeat them as a job you do while the alarm is sounding.

If a Gas Safe engineer later says the boiler should be replaced, the price and what should be written on the quote are in what sits inside a price for a replacement boiler. A heat pump grant in England and Wales is whether the Boiler Upgrade Scheme is still open. Neither page is a quote from this site.

After the emergency line, who works on the appliance

Stay out until you have advice. The call you have already made is to the gas emergency service, or to the medical line. It is not a booking on this directory.

Gas work after that comes back to a Gas Safe registered engineer. Who may do it is on who is allowed to work on gas in a home. HSE says anyone employed to work on gas appliances in a home must be on the register and competent for that work. If you are unsure, HSE gives Gas Safe Register as 0800 408 5500. Ask to see the card when they arrive. Oil, wood and coal appliances need a competent person for that fuel, and a chimney that is swept. The plumbing list on this site is for gas heating and the other plumbing work those businesses name.

Open the plumbing and heating list, including London, Manchester, Birmingham, Leeds and Bristol. Gas Safe on a card is shown only when that record already has it. Get contact details opens the list. It does not confirm the registration and it does not pass the job on.