Key takeaways
- Scotland has required interlinked alarms in every home, owner-occupied included, since 1 February 2022. England requires one alarm per storey in rented homes only, and does not require interlinking at all.
- Wales goes further than England for rented homes: at least one alarm per storey, connected to the mains and linked to the other alarms, under the Renting Homes fitness rules that started on 1 December 2022.
- Northern Ireland’s private tenancy rules, in force from 1 September 2024 for new tenancies, require interlinked smoke and heat alarms installed to BS 5839-6.
- We read the top ten of Amazon UK’s Smoke Alarms chart on 1 October 2026. None of the ten said in its own listing that it interlinks, and the only one to mention interconnection said it does not support it.
Smoke alarm sales climb every autumn, and the reason is on the calendar. The clocks go back on 25 October this year, and that weekend is when most UK fire services tell people to test their alarms. Heating season starts around the same time. Amazon’s Smoke Alarms chart reflects it: the FireAngel FA6620 sits at number one in the category today at £11.98, with another eight battery alarms behind it.
Here’s the problem with buying off that chart. The law on smoke alarms is not one UK law. It’s four, they disagree with each other on the single most expensive detail, and the chart is quietly selling the version that only works in one of the four nations.
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The interlinking split, and why it decides what you buy
Interlinked means the alarms talk to each other. One detects smoke in the kitchen, every alarm in the house sounds. A standalone alarm just sounds where it is, which is no help if the fire starts two floors below you while you sleep.
In Scotland, interlinking is compulsory everywhere. The requirement was added to the tolerable standard under the Housing (Scotland) Act 1987, and an amendment order made in January 2021 pushed its start date to 1 February 2022. The Scottish Government’s own guidance sets out the minimum: one smoke alarm in the living room or the room you use most, one in every hallway and landing, one heat alarm in the kitchen, all mounted on the ceiling and all interlinked. It applies whether you rent or own.
In England, the picture is almost the opposite. The 2015 regulations, as amended in 2022, cover rented homes only, and the government’s landlord guidance is explicit that at least one alarm goes on every storey used as living accommodation. On power and linking it says the regulations “do not stipulate the type of alarms”, mains or battery. Interlinking is not in there. If you own your home in England, no law tells you to fit anything.
Wales sits between the two and lands closer to Scotland for renters. The fitness for human habitation guidance requires a working smoke alarm on every storey, and says it must be connected to the electrical supply and linked to the other smoke alarms. One hard-wired linked alarm per storey is the floor; extras above that can be battery and unlinked. The duty started on 1 December 2022, with a year’s grace for homes that already had people living in them.
Northern Ireland is newest. The Smoke, Heat and Carbon Monoxide Alarms for Private Tenancies Regulations (Northern Ireland) 2024 came into operation on 1 September 2024 for new private tenancies and 1 December 2024 for the rest. Regulation 3 wants a smoke alarm in the main daytime living room and in every circulation space on each storey, plus a heat alarm in every kitchen. Regulation 4 says those smoke and heat alarms “must be interlinked”, and allows either hard wiring or sealed battery units, installed to BS 5839-6. Carbon monoxide alarms, it adds, do not need to be interlinked.
So three of the four nations require interlinking somewhere, and the one that doesn’t is the one whose market the bestseller chart is built on.
What we found on the chart
We read the Amazon UK Smoke Alarms subcategory chart on 1 October 2026 and opened all ten top-selling products, checking the product title and the seller’s own feature bullets for any mention of interlinking or interconnection. Not one of the ten claimed it. The single product that raised the subject was the X-Sense SC07 combined smoke and carbon monoxide alarm at number ten, whose listing states it “does not support interconnectivity”.
That is a claim about what the listings say, not a lab finding about what the hardware can do. Some of these alarms may well have interlinkable siblings in the same range. The point stands either way: a Scottish homeowner reading that chart gets no signal at all that nine tenths of it will leave them short of the standard, and the cheapest route to compliance is a pre-linked bundle rather than three separate chart-toppers.
How we picked these
We started from the Amazon UK Smoke Alarms chart read on 1 October 2026, then selected for role rather than rank, because the right alarm here depends on which nation you’re in and which room you’re fitting. Every product below was opened on Amazon on the day of writing and its title, price and category rank read from the live page. We have not fire-tested these alarms. The legal requirements were read at the relevant government sources and legislation, each linked at the foot of the page.
| Alarm | Best for | Interlinks | Power | Price |
|---|---|---|---|---|
| FireAngel FA6620 | A single storey in England | No | Sealed 10-year battery | £11.98 |
| X-Sense HS21 bundle | Scotland’s full standard in one box | Yes | Sealed 10-year battery | £49.19 |
| Pre-connected 3-pack | Cheapest pre-linked smoke set | Yes | Sealed 10-year battery | £41.99 |
| FireAngel FA6720-R | The kitchen heat alarm | No | Sealed 10-year battery | £11.97 |
| FireAngel SW1-R | Welsh rented homes | Wired | Mains with 9V backup | £17.09 |
| FireAngel ST-622T | Hallways next to a kitchen | No | Sealed 10-year battery | £21.46 |
The six we would buy
FireAngel FA6620 optical smoke alarm
£11.98 on 1 October 2026 · number 1 in Smoke Alarms
The chart topper, and for an English household it does the job the law asks for. Optical sensing, which responds well to the slow smouldering fires that start in furniture and wiring, and a sealed battery rated for ten years so there is no annual beeping and no 9V to forget. At twelve quid you can put one on each storey and still have change.
The catch: it is standalone. Buy three and they will not talk to each other, so a fire downstairs will not wake you upstairs. In Scotland that leaves you short of the tolerable standard whether you own or rent.
X-Sense HS21 interlinked smoke and heat alarm bundle
£49.19 on 1 October 2026 · number 32 in Smoke Alarms
Two smoke alarms and one heat alarm, interlinked, with sealed ten-year batteries. That maps exactly onto the Scottish minimum in a typical flat or small house: one smoke alarm in the main living room, one in the hall, a heat alarm in the kitchen. No wiring, no electrician, and because the heat alarm comes from the same family it joins the same link.
The catch: three alarms covers a flat or a two-up two-down, and no more. Scotland wants a smoke alarm in every hallway and landing, so a three storey house needs another unit, and the listing says the kit does not work with the brand’s base station or app.
Pre-connected interlinked smoke alarms, 3 pack
£41.99 on 1 October 2026
Three interlinked smoke alarms that arrive already paired, so there is no pairing sequence to work through on a stepladder. Sealed ten-year batteries again. Seven pounds cheaper than the X-Sense kit and the obvious pick if your kitchen heat alarm is already sorted, or if you want linked smoke cover across three floors.
The catch: there is no heat alarm in the box, and you cannot just add one from another brand, because interlinking only works within a single manufacturer’s family. For a Scottish kitchen that means buying a matching heat alarm from the same range, which pushes the real cost past the X-Sense bundle.
FireAngel FA6720-R heat alarm
£11.97 on 1 October 2026 · number 6 in Smoke Alarms
A kitchen needs a heat alarm rather than a smoke alarm, which is why Scotland and Northern Ireland both name one specifically. It triggers on temperature instead of particles, so grilling bacon and a smoking oven do not set it off. Ten-year sealed battery, same price as the smoke alarm above.
The catch: a heat alarm is slower than a smoke alarm by design, so it is a kitchen-only device and should never be the alarm covering a hall or bedroom. This one is also standalone, so it satisfies the “heat alarm in the kitchen” half of the Scottish rule and not the interlinking half.
FireAngel SW1-R mains smoke alarm with backup battery
£17.09 on 1 October 2026 · number 7 in Smoke Alarms
Wales is the one nation that puts “connected to the electrical supply” in writing for rented homes, so a battery alarm will not do there however good it is. This is a mains unit with a 9V backup for power cuts, using the same optical sensor as the FA6620, and it is the cheapest route into the Welsh requirement that we found on the chart.
The catch: mains means an electrician, which costs more than the alarm. The listing also says nothing at all about linking it to other alarms, and Welsh rules want the per-storey alarms linked, so check the wiring spec with your installer before you buy a houseful.
FireAngel ST-622T Thermoptek multi-sensor alarm
£21.46 on 1 October 2026 · number 9 in Smoke Alarms
A multi-sensor reads smoke and heat together and weighs one against the other, which is what you want in a hall that opens onto the kitchen. Those are the spots where people disconnect alarms out of sheer irritation, and a disconnected alarm protects nobody. Ten-year sealed battery.
The catch: nearly double the price of the FA6620 for one unit, and still standalone. In an open-plan layout it can also sit in the awkward middle ground where Scottish guidance expects a heat alarm in the kitchen zone regardless.
Questions people ask
Do I legally need a smoke alarm if I own my home?
In Scotland, yes. The tolerable standard has covered owner-occupied homes since 1 February 2022 and asks for interlinked alarms. In England, Wales and Northern Ireland the alarm duties sit on landlords, so there is no equivalent requirement on an owner-occupier.
How many smoke alarms does a landlord have to fit in England?
At least one on every storey used as living accommodation. The government’s guidance for the private rented sector adds that the regulations do not stipulate mains or battery, and they say nothing about interlinking.
What counts as interlinked?
Alarms that sound together, so one detecting smoke sets off all of them. It can be done over radio between sealed battery units or by wiring between mains units. Northern Ireland’s 2024 regulations allow either, as long as the install follows BS 5839-6.
Can I mix brands when I interlink?
Treat the answer as no. Radio interlinking uses each manufacturer’s own protocol, so a heat alarm from one brand will not generally join a smoke alarm from another. Buy the whole set from one range.
Why a heat alarm in the kitchen rather than a smoke alarm?
Because cooking produces exactly what a smoke sensor is looking for. A heat alarm responds to temperature rise instead, which is why both the Scottish standard and regulation 3 of the Northern Ireland rules name a heat alarm for kitchens specifically.
When should I test them?
Monthly is the usual advice, and the clocks going back on 25 October is the reminder most people actually act on. A sealed ten-year alarm still needs testing; the sealed battery removes the annual replacement, not the monthly press.
Sources
- mygov.scot, Home fire safety
- Scottish Government, Fire and smoke alarms in Scottish homes
- Housing (Scotland) Act 1987 (Tolerable Standard) (Extension of Criteria) Amendment Order 2021, SSI 2021/46
- GOV.UK, Smoke and Carbon Monoxide Alarm (England) Regulations 2015 Q&A booklet
- Welsh Government, Fitness for human habitation guidance
- Smoke, Heat and Carbon Monoxide Alarms for Private Tenancies Regulations (NI) 2024, regulation 3
- Smoke, Heat and Carbon Monoxide Alarms for Private Tenancies Regulations (NI) 2024, regulation 4
- GOV.UK, When do the clocks change
Prices and chart positions were read on Amazon.co.uk on 1 October 2026 and will have moved since. Look Into is a participant in the Amazon EU Associates Programme and earns from qualifying purchases; this does not change what we recommend or what we say about it. This article explains what the rules require and is not legal advice.
This page is part of Look Into’s UK household cost research. For the costed figures behind it — capture date, method and sources — see the UK Home Security Value Index.