Nothing about smoke alarms changed in 2026. Two separate rulebooks apply and they answer different questions. If you are building or altering, Approved Document B asks for a fire detection and alarm system of at least Grade D2 Category LD3, and a new habitable room above or below the ground storey brings that with it. If you let the property, a working smoke alarm belongs on every storey used as living accommodation, a duty that has run since 1 October 2015 and was widened, not started, on 1 October 2022. If you simply live in your own house and are not building, England requires nothing of you.
Rulebook one
You are building or altering
The Building Regulations, through Approved Document B. The question is whether the system itself is up to standard: minimum Grade D2 Category LD3, mains operated, with a standby supply. Applies to owner-occupiers and landlords alike, because it follows the work rather than the tenure.
Rulebook two
You let the property
The Smoke and Carbon Monoxide Alarm Regulations, in force since 1 October 2015 and amended from 1 October 2022. The question is whether a working alarm is there: one per storey, plus a carbon monoxide alarm where a fixed combustion appliance sits. The type of alarm is deliberately left open.
The version of Approved Document B Volume 1 in force is the 2019 edition incorporating 2020, 2022 and 2025 amendments collated with 2026 and 2029 amendments, and its page on GOV.UK was last updated on 11 March 2025. The letting duties date from 1 October 2015 and took their present shape on 1 October 2022. Those 2026 and 2029 amendment documents are where the yearly wave of new rules headlines comes from, and this is what they cover:
Neither has anything to do with alarms in homes. If a page promises you new alarm rules for this year, it is selling the year, not the rule.
Source: GOV.UK, Approved Document B Volume 1: Dwellings, 2019 edition incorporating 2020, 2022 and 2025 amendments collated with 2026 and 2029 amendments, Section 1, checked 13 August 2026.
This is the side that catches most renovations, and it applies whether you live in the house or let it out. The quotes below are the working text, straight from the Approved Document.
The level the system has to reach
All dwellings should have a fire detection and alarm system, minimum Grade D2 Category LD3 standard, in accordance with the relevant recommendations of BS 5839-6. A higher standard of protection should be considered where occupants of a proposed dwelling would be at special risk from fire.
Approved Document B Volume 1, paragraph 1.1
The grade describes the power supply and the equipment, the category describes how much of the home is covered. Both definitions live inside BS 5839-6, a British Standard you have to buy, which is the reason this page quotes the Approved Document rather than the standard behind it.
What the alarms themselves have to be
Smoke alarms should be mains operated and conform to BS EN 14604. Heat alarms should be mains operated and conform to BS 5446-2. Smoke and heat alarms should have a standby power supply, such as a battery (rechargeable or non-rechargeable) or capacitor.
Approved Document B Volume 1, paragraphs 1.2 to 1.4
Mains operated with a standby power supply. That is a first fix job with a cable run, not a unit you stick to the ceiling at the end of the build, which is why the position of every alarm is worth settling before the plasterboard goes on.
When an extension or alteration brings this into play
A fire detection and alarm system should be installed where either of the following applies. a. A new habitable room is provided above or below the ground storey. b. A new habitable room is provided at the ground storey, without a final exit. Smoke alarms should be provided in the circulation spaces of the dwelling in accordance with paragraphs 1.1 to 1.4.
Approved Document B Volume 1, paragraphs 1.8 and 1.9
This is the paragraph most home projects meet. A loft bedroom, a basement room and a ground floor room with no way straight out all land here. A habitable room in Volume 1 means a room people live in, counting a kitchen but not a bathroom.
Large houses ask for more
A large dwellinghouse has more than one storey, and at least one storey exceeds 200m2. A large dwellinghouse of two storeys (excluding basement storeys) should be fitted with a Grade A Category LD3 fire detection and alarm system, as described in BS 5839-6. A large dwellinghouse of three or more storeys (excluding basement storeys) should be fitted with a Grade A Category LD2 fire detection and alarm system as described in BS 5839-6.
Approved Document B Volume 1, paragraphs 1.5 to 1.7
Grade A is a different animal from the alarms most people picture: a system with its own control and indicating equipment. The trigger is floor area per storey, so a wide single storey extension can move a house into this bracket.
Paperwork at the end
Fire detection and alarm systems must be properly designed, installed and maintained. A design, installation and commissioning certificate should be provided for fire detection and alarm systems.
Approved Document B Volume 1, paragraph 1.14
Ask for that certificate at handover and keep it with the electrical certificates. It is the document that answers the question years later when a buyer, a surveyor or an insurer asks what was installed and by whom.
Sources: GOV.UK, Approved Document B Volume 1: Dwellings, 2019 edition incorporating 2020, 2022 and 2025 amendments collated with 2026 and 2029 amendments, Section 1, checked 13 August 2026; GOV.UK, Approved Document B fire safety: frequently asked questions, checked 13 August 2026. The government guidance confirms the level in as many words: for the purposes of Part B of the Building Regulations a Grade D2 Category LD3 system is considered to be adequate. Table 1 of BS 5839-6:2019 itself recommends the heavier Grade D1 Category LD2, so a designer working to the standard may land above the regulatory minimum.
The legal hook is not in the Approved Document but in the regulations behind it. Paragraph B1, means of warning and escape, is one of the relevant requirements, so work that touches it is caught.
When work counts as a material alteration
An alteration is material for the purposes of these Regulations if the work, or any part of it, would at any stage result, (a) in a building or controlled service or fitting not complying with a relevant requirement where previously it did; or (b) in a building or controlled service or fitting which before the work commenced did not comply with a relevant requirement, being more unsatisfactory in relation to such a requirement.
The Building Regulations 2010, regulation 3(2)
A relevant requirement is a defined list, and paragraph B1, means of warning and escape, is on it, alongside Part A, paragraphs B3, B4 and B5, Part M and Part T. That is the hook: change the escape route or the room layout and B1 is in scope.
The level the finished work has to reach
Building work shall be carried out so that, after it has been completed, (a) any building which is extended or to which a material alteration is made; or [...] complies with the applicable requirements of Schedule 1 or, where it did not comply with any such requirement, is no more unsatisfactory in relation to that requirement than before the work was carried out.
The Building Regulations 2010, regulation 4(3), limbs (b) and (c) omitted
The two limbs behind the [...] deal with work on controlled services and fittings and the buildings connected to them; they are left out here only because this page is about work on the dwelling itself. Renovating does not automatically drag the whole house up to new build standard. It does mean the work cannot leave you worse off than you started. How that lands on your particular job is a matter for the building control body looking at it.
Sources: legislation.gov.uk, The Building Regulations 2010, regulation 3 (meaning of building work), checked 13 August 2026; legislation.gov.uk, The Building Regulations 2010, regulation 4 (requirements relating to building work), checked 13 August 2026.
Which approval you are dealing with here is building control, not planning. The difference between the two is set out in planning permission versus building regulations.
The points below turn up all over the internet as Building Regulations requirements. They are not in the Approved Document, and knowing that saves you an argument with an installer who quotes them at you.
Interlinking
Section 1 of Volume 1 does not use the word. It sets Grade D2 Category LD3 and refers to BS 5839-6, and what those labels mean sits inside that standard. In practice an installer designing to the standard will link the alarms, but the linking requirement is not a sentence you can read in the Approved Document.
A heat alarm in every kitchen
Volume 1 asks for one in a single place: paragraph 3.21, as part of one option for multi-storey flats without their own external entrance at ground level, where a protected stairway comes with additional smoke alarms in all habitable rooms and a heat alarm in any kitchen. There is no blanket kitchen rule for houses in the Approved Document.
Spacing figures such as 7.5m from a bedroom door
That figure does appear in Volume 1, but in the escape route rules about storeys above ground level, not about where an alarm goes. Alarm positions come from BS 5839-6.
None of this makes a linked system a bad idea. It makes it a design decision taken with your installer and your building control body, rather than a line you can point at in a free document.
Carbon monoxide sits in a different Approved Document, and this is the part of the rules most likely to surprise someone doing a modest renovation. Replacing an appliance is enough to trigger it.
Which appliances
A carbon monoxide alarm should be fitted upon the installation of fixed combustion appliances that burn solid fuels, gas fuels (excluding gas appliances used solely for cooking) and oil fuels.
Circular letter, new edition of Approved Document J
A wood burner, a gas boiler and an oil boiler are all in. A gas hob on its own is not.
Which homes
A carbon monoxide alarm should be fitted upon the installation of fixed combustion appliances in new homes and when new or replacement fixed combustion appliances are installed in existing homes.
Circular letter, new edition of Approved Document J
This is the sentence that catches renovations. Swapping an old boiler for a new one, or putting a stove into a reopened fireplace, brings the alarm with it even though the rest of the house is untouched.
Which alarm
Carbon monoxide alarms should comply with British Standard BS EN 50291. Alarms should be powered by a battery designed to operate for the working life of the alarm. Alarms should also have a warning device to alert users when the working life of the alarm is due to pass. Alternatively, a mains-powered alarm with fixed wiring (not plug-in) should be fitted provided the alarm has a sensor failure warning device.
Circular letter, new edition of Approved Document J
A sealed long life battery unit is acceptable. A plug-in alarm is not.
Where it goes
A carbon monoxide alarm should be located in the same room as the combustion appliance and on the ceiling at least 300mm from any wall or on a wall, as high up as possible (above any doors and windows) but not within 150mm of the ceiling and between 1m and 3m horizontally from the appliance.
Circular letter, new edition of Approved Document J
Same room as the appliance, not the hallway outside it.
Who signs it off
The fitting of carbon monoxide alarms upon the installation of new and replacement fixed combustion appliances in existing dwellings will most likely be carried out by installers registered with Gas Safe Register or a Building Regulations competent person scheme. This is work that does not require a building notice, initial notice or amendment notice to be given or full plans to be deposited.
Circular letter, new edition of Approved Document J
Your installer self-certifies the work under regulation 20, so there is usually no separate building control visit. Ask for the certificate, because that is the only paper trail the job leaves behind.
Source: GOV.UK, Circular letter: new edition of Approved Document J, 27 September 2022, checked 13 August 2026. These provisions came into force on 1 October 2022, subject to transitional arrangements for work already under way.
If a boiler swap is what brought you here, the price side of that job sits in new boiler cost.
A separate rulebook, a different question, and one that does not care whether any building work is happening. The duties start on 1 October 2015, not in 2022, which is the single most repeated error on this subject. The regulations apply to all social and private rented tenancies, other than those explicitly excluded in the Schedule to the Regulations.
A smoke alarm on every storey with a room used as living accommodation
at least one smoke alarm is equipped on each storey of their homes where there is a room used as living accommodation
GOV.UK guidance for landlords and tenants
Counted per storey, not per bedroom, and this duty has run since 1 October 2015 rather than 2022. Living accommodation is wider than it sounds: the guidance says in as many words that a bathroom or lavatory is classed as living accommodation, and that a hall or landing is classed as a room. So a loft with only a shower room, or a converted cellar with only a cloakroom, is still a storey that needs an alarm.
A carbon monoxide alarm where a fixed combustion appliance sits
a carbon monoxide alarm is equipped in any room used as living accommodation which contains a fixed combustion appliance (excluding gas cookers)
GOV.UK guidance for landlords and tenants
Since 2022 this covers gas and oil appliances too, not solid fuel alone. The regulations say fixed combustion appliance other than a gas cooker.
Working alarms on day one of a new tenancy
check that each prescribed alarm is in proper working order on the day the tenancy begins if it is a new tenancy
GOV.UK guidance for landlords and tenants
Repair or replace once you are told
Ensure smoke alarms and carbon monoxide alarms are repaired or replaced once informed and found that they are faulty
GOV.UK guidance for landlords and tenants
The regulations put a pace on it: as soon as reasonably practicable after the report.
No alarm type is prescribed
The regulations do not stipulate the type of alarms (such as mains powered or battery powered)
GOV.UK guidance for landlords and tenants
So interlinked is not a letting requirement. If the same property is having building work done, the Building Regulations side of this page is where the equipment standard comes from.
Where the guidance suggests putting them
Smoke alarms should be fixed to the ceiling in a circulation space, i.e. a hall or a landing. Carbon monoxide alarms should be positioned at head height, either on a wall or shelf, approximately 1-3 metres away from a potential source.
GOV.UK guidance for landlords and tenants
Presented as advice in the guidance rather than as a rule in the regulations.
What happens if you do not
local authorities who can impose a fine of up to £5,000 where a landlord fails to comply with a remedial notice
GOV.UK guidance for landlords and tenants
Fines are applied per breach, and the council is the enforcing body.
What the 1 October 2022 amendment actually did, since that is the date every summary quotes as if the smoke alarm duty began there:
Tenancies outside the regulations include:
Low cost ownership accommodation was added to that list of exclusions by the 2022 amendment. The move of social housing providers in the other direction, into scope, sits in the list of changes above.
Sources: GOV.UK, Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022: guidance for landlords and tenants, checked 13 August 2026; legislation.gov.uk, The Smoke and Carbon Monoxide Alarm (England) Regulations 2015 (SI 2015/1693), regulation 4, checked 13 August 2026; legislation.gov.uk, The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 (SI 2022/707), checked 13 August 2026. The fine reaches £5,000 per breach and the council enforces it. The guidance carries its own caveat: This booklet is not an authoritative interpretation of the law, but intended as a general guide.
England has no general retrofit duty for owner-occupiers. If you are not doing building work, no rule tells you to fit an alarm.
we will encourage residents in all homes, including owner-occupiers, to ensure they have adequate smoke alarm coverage
Government response to the consultation on extending the regulations
When the extension of the regulations was consulted on, the government chose encouragement over legislation for owner-occupied homes, and pointed at the Fire Kills campaign run with the National Fire Chiefs Council. That campaign asks for an alarm on every level and a test every month.
Source: GOV.UK, Domestic smoke and carbon monoxide alarms: proposals to extend regulations, government response, checked 13 August 2026.
Scotland works the other way round: the standard applies to every home there, whatever the tenure and whatever the age of the house.
Interlinked alarms means if one goes off, they all go off, so you will always hear an alarm wherever you are in your home. It is the property owner’s responsibility for meeting the standard.
So a Scottish article about your legal duty to fit interlinked alarms is accurate for Scotland and simply does not describe the position in England. Wales and Northern Ireland set their own rules and have not been checked for this page, so nothing here should be read across to them.
Source: gov.scot, Fire and smoke alarms in Scottish homes, checked 13 August 2026.
There is no official or statistical price source for alarm installation, so everything below comes from commercial guides that are trying to win the work. They are quoted separately, with their own dates, rather than averaged into one number that would hide how far apart they sit.
Per alarm, supply and labour combined
VAT treatment is not stated.
MyJobQuote, Smoke alarm cost: how much to install a fire alarm, last updated 24 March 2026, checked 13 August 2026.
Whole house, and separate unit prices
VAT treatment is not stated.
Logic Fire and Security, Smoke alarm installation cost guide: what to expect in 2026, checked 13 August 2026.
One electrician’s published price list, south east England
All figures exclude VAT.
Prices cover Tonbridge, Tunbridge Wells, Sevenoaks and Crowborough, and the quote includes collecting and disposing of the old units.
Bright Spark Electrical Services, How much does it cost to install mains smoke, heat and carbon monoxide alarms, 2026 prices, checked 13 August 2026.
Read across the three and the same house lands in two different places. One guide prices a whole three bedroom home on mains interlinked alarms at £220 to £300. On the electrician’s list, a first alarm plus two more is from £345 before VAT, made up of £185 for the first alarm plus £80 for each of two more. That is 1.15 to 1.57 times the whole house figure, or 1.38 to 1.88 times at £414 with VAT added at 20 per cent. Every figure on the electrician’s list is a from price, so it is a floor rather than a quote, and the whole house guide does not say whether VAT sits inside its number. The comparison is a sense of scale, not a like for like. I quote the guides separately rather than averaging them, because an average would hide the thing you actually need to ask about. What moves the number:
Two quotes are only comparable once you know how many alarms each one covers, whether the units are in the price and whether VAT is. Those are the same three questions that decide most of the arguments in why quotes differ. If the alarms are part of a bigger electrical job, the surrounding costs sit in rewiring cost and consumer unit replacement cost.
Mains alarms with a standby supply mean cable runs, and cable runs are first fix work. Where each alarm goes, and whether the cable is already there, is settled before the plasterboard arrives. After that, every change is a chase in a finished wall.
Check it before the walls close up
Alarm positions, cable runs and the certificate to ask for at the end all belong on the same walk round the site. The free checklist covers the rest of what disappears behind the boards.
Open the first fix checklistIf the work in question is a loft bedroom, which is the case paragraph 1.8 is written for, the budget side of it sits in loft conversion cost.
This page is an explanation of published rules, not legal advice and not a substitute for the decision on your own project. Where building work is involved, the building control body handling it is the one that judges whether what you have built meets the requirement.
No. The alarm provisions sit in Section 1 of Approved Document B Volume 1, whose current edition is the 2019 edition incorporating 2020, 2022 and 2025 amendments collated with 2026 and 2029 amendments. On the letting side, the duty to have a smoke alarm on every storey used as living accommodation has run since 1 October 2015, and the last change to those regulations was on 1 October 2022, which widened the carbon monoxide duty rather than starting the smoke alarm one. The 2026 and 2029 amendment documents to Approved Document B cover sprinklers in new care homes and the withdrawal of the old national fire testing classes in favour of BS EN 13501. Neither touches alarms in homes.
In England, no. When extending the alarm regulations was consulted on, the government chose to encourage owner-occupiers through the Fire Kills campaign rather than to require anything of them. Scotland is the opposite: there the standard applies to every home whatever the tenure, and meeting it is the property owner’s responsibility.
Paragraph 1.8 of Approved Document B Volume 1 asks for a fire detection and alarm system where a new habitable room is provided above or below the ground storey, or at the ground storey without a final exit. A loft bedroom is the textbook case. What that means for your particular layout is settled by the building control body looking at the job, not by a page like this one.
The letting regulations say in as many words that they do not stipulate the type of alarm, so interlinking is not a letting duty. Approved Document B does not use the word either: it sets a minimum grade and category and refers to BS 5839-6, and those definitions live inside that standard, which is not free to read. An installer designing to the standard will normally link them.
Approved Document J has asked for a carbon monoxide alarm on the installation of a fixed combustion appliance burning solid fuel, gas other than a cooker, or oil since 1 October 2022, in new homes and when a new or replacement appliance goes into an existing home. Replacing a boiler is enough to bring it in. The installer self-certifies the work, so the certificate is the only paper trail it leaves.