Stay safe and get an early warning of a fire with the smartest, most effective smoke detectors for every budget
Fire and rescue services attended over 178,000 fires in the year to March 2023 in England alone, and while the number of fire fatalities dropped to their lowest ever figure, 259 people still lost their lives. Buying a smoke alarm is one of the most important steps you can take to protect your home, your life and the lives of your family and friends. It can give you early warning of a fire before it spreads, and the best chance of getting everyone safely out of the house.
In fact, most homes require more than one smoke alarm, alongside detectors for carbon monoxide (CO) and heat. These protect you against the notorious silent killer, or cover areas such as the kitchen, where fires can originate but a smoke alarm would be impractical. And while it’s not hard to find a decent smoke alarm at an affordable price, there are some older or less effective models out there, and there are a few options or features that you might want to look out for. We’re here to tell you what those are and steer you towards the best smoke alarm for you.
How to choose the best smoke alarm for you
Smoke alarms come in two basic types, which differ in the way they sense smoke. In the first, a tiny amount of a radioactive isotope (far too small to cause any harm) causes ionisation in the air within the smoke alarm. Should any smoke enter, these ionised air molecules react, causing a change in the electrical behaviour, which triggers the alarm. These ionisation alarms are sensitive and quick to react, but also prone to false alarms. Hence the classic smoke alarm annoyance of going off every time you burn your toast.
The second type uses an optical sensor, which sees smoke as it enters the sensor chamber, setting the alarm off. These are quick to detect smouldering fires that produce a lot of smoke – the kind you get when upholstery and soft furnishings catch – but aren’t quite as sensitive to other types of fire. However, the difference isn’t huge, and they’re less likely to be triggered accidentally when cooking.
As a rule of thumb, it’s best to use optical alarms in living rooms, bedrooms or downstairs hallways where you either have a lot of upholstered furniture and soft furnishings or the alarm is likely to be set off by cooking fumes. Keep ionisation alarms for upstairs hallways or areas where dust or exposure to the elements (say, through an open door) might potentially set off an optical sensor. If in doubt, go optical or use a multi-sensor alarm. Use of ionisation alarms is generally being discouraged by many fire services, and some manufacturers have now discontinued their ionisation products.
For kitchen, garage or workshop use, fire services also recommend fitting a heat alarm. These sense hot air rather than smoke, and trigger when the air in the sensor chamber reaches a specific temperature, which is usually 58°C. Heat alarms are slower to respond than actual smoke alarms, but they’re also not as prone to false alarms. They won’t go off when you’re grilling sausages or burning toast, but they still provide ample warning if something catches fire in your kitchen.
Different makes and models will be slower or faster to detect smoke coming through and have different alarms working at different volumes. Some even feature voice alarms or strobing lights. However, any alarms sold in the UK have to meet BS EN 14604:2005, which specifies the requirements, tests and performance criteria for smoke alarms using optical or ionisation sensors. Heat alarms are governed by the separate BS 5446-3:2003 standard.
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What about the battery?
Batteries used to be the weakness of most household smoke alarms, requiring replacement every year or so and usually running out of charge, causing the low battery alarm to ring, often in the middle of the night. As with carbon monoxide alarms, the trend is now towards alarms with a built-in, 10-year lithium battery, designed to work for the alarm’s effective lifespan. In Scotland, these are now a legal requirement. In England and Wales, however, you can still buy and use alarms with a replaceable 9V battery, and these often work out cheaper. We’d recommend paying extra for the convenience and peace of mind, but the choice is yours.
Is there anything else worth looking out for?
In 2022, Scotland added further legal requirements that smoke alarms fitted in a home be interlinked, so that if one goes off, they all go off. This usually means buying a pack of interlinked alarms, which connect over a dedicated RF connection rather than Bluetooth, Wi-Fi, Zigbee or any other wireless standard. You’re required to have a smoke alarm in your living room and every hallway or landing, along with a heat alarm in the kitchen.
Of course, it’s entirely possible to get connected smoke alarms that hook up directly to your home network via Wi-Fi, or through a proprietary connection or a Zigbee or Z-Wave hub. The advantage with these is that they can warn you of a fire through an alarm or alert on your smartphone, and also, with some systems, trigger smart lighting to come on.
How we test smoke alarms
We test smoke alarms using an aerosol tester, sprayed in the direction of the alarm for up to five seconds from a distance of 30cm. If the alarm doesn’t respond within four seconds, we don’t recommend it. Having completed this functional test, we take a careful look at any controls, screens or indicators to see how clear and effective they are.
We then look at any instructions and fittings provided, to see how easy it would be to fit the alarm to a wall or ceiling. Wherever the alarms still use replaceable batteries, we check how simple and easy these are to replace.
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The best smoke alarms you can buy in 2024
1. Google Nest Protect: Best smart smoke and carbon monoxide alarm
Price when reviewed: £99 | Check price at Amazon While there are other smart smoke alarms, the Nest Protect is in a league of its own. It connects to the internet through Wi-Fi and sends reports to your phone or tablet via the iOS or Android app. When it senses smoke, it delivers several verbal warnings before activating the 85dB alarm, giving you just enough time to deactivate the alarm through the app or by waving at the built-in motion detector before you get an earful. It also detects carbon monoxide and can even tell your Nest thermostat to turn off the boiler if it detects a leak.
Meanwhile, a system of colour-coded indicators on the central ring gives you visual alerts and updates, and even a subtle night light if you pass it in the dark. It’s more expensive than other smoke alarms, but if you’re invested in making your home smarter, this is the alarm to buy.
Key specs – Type: Split-spectrum optical; Battery type: 6 x AA lithium; Display: LED ring indicator; Alarm volume: 85dB; Connectivity: 802.11n Wi-Fi; Interconnected: No
2. FireAngel Pro Connected: The best connected smoke alarm
Price when reviewed: £73 | Check price at Screwfix As just a smoke alarm, the Pro Connected is expensive, but it comes into its own when you pair it with another Pro Connected unit or hook it up via Wi-Fi as a smart alarm. You can connect smoke alarms, heat alarms and CO alarms from the Pro Connected range so that, should one go off, they all go off. This and the 10-year sealed-in battery means they’re compliant with recent changes to Scottish legislation, and that you won’t miss out on an alarm if you live in a larger property, have a hearing impairment or spend a lot of time with the TV blaring or your headphones on.
Add the £50 Gateway and you can connect your alarms through your Wi-Fi network to the FireAngel Connected App, with instant alerts via app or email and the ability to run tests from the app or through an Alexa Skill. You can also monitor alerts across a couple of properties, which might be handy if you have elderly parents or a business premises to keep tabs on. Like the FireAngel ST-622Q below, it uses the firm’s Thermoptek sensor, giving it high sensitivity without excessive false alarms.
Key specs – Type: Thermoptek optical; Battery type: Internal lithium, 10-year lifespan; Display: Red/amber LEDs; Alarm volume: 85dB; Connectivity: Wi-Safe 2; Interconnected: Yes
3. Kidde 10Y29: Best simple smoke alarm
Price when reviewed: £15 | Check price at Amazon Looking for a low-cost alarm you can fit and forget? Say hello to the Kidde 10Y29. It’s easy to mount, easy to activate and couldn’t be much easier to use. The sealed-in battery lasts 10 years, while a single button tests the alarm and hushes it should it go off inadvertently. Cleverly, the alarm starts quietly during testing, only ramping up to the full 85dB racket if you hold the test button for five seconds. Meanwhile, hushing the alarm shuts it up for five seconds, giving you a little time to clear the air of your burnt toast smoke. Dense smoke will override the mute, so you’ll still be safe.
The 10Y29 responded quickly to simulated smoke in testing and, at full tilt, the alarm is loud enough to wake heavy sleepers, if not the dead. It’s a great smoke alarm that just works.
Key specs – Type: Optical; Battery type: Internal lithium, 10-year lifespan; Display: Red LED; Alarm volume: 85dB; Connectivity: N/A; Interconnected: No
4. FireAngel ST-622Q: Best long-life smoke alarm
Price when reviewed: £22 | Check price at Amazon If you don’t need the smart features of the Pro Connected range, the ST-622Q gives you FireAngel’s Thermoptek sensor tech at a much more affordable price. Thermoptek combines an optical sensor with a temperature sensor, increasing the sensitivity of the optical sensor as the temperature increases. The idea is to give faster responses to all types of fire without creating extra false alarms, and we found it speedy and accurate in our tests.
If it does go off inadvertently, the large, central test/mute button makes it easy to silence, saving your ears from a thrashing. As with the Pro Connected, it buys you ten minutes to clear the air, while a “sleep easy” function gets you eight hours of quiet if you press the button once the low battery warning starts. Little touches such as this elevate the ST-622Q above your run-of-the-mill smoke alarms, making it one of the best options for most households.
Key specs – Type: Thermoptek optical; Battery type: Internal lithium, 10-year lifespan; Display: Red LED; Alarm volume: 85dB; Connectivity: N/A; Interconnected: No
5. Kidde 29HD: Best budget smoke alarm bundle
Price when reviewed: £21 | Check price at Amazon Kitting out a home with smoke alarms can get expensive, which makes this bargain bundle quite appealing. You’re effectively getting two alarms for little more than the price of one, and with optical sensors, test and hush buttons and batteries included, you’re not losing out on must-have features.
In fact, there are just two downsides. First, we’re back to alkaline 9V batteries rather than a modern 10-year lithium battery, so you’ll have to replace them every year. That also means this alarm doesn’t comply with the Scottish law that comes in during 2022. Second, you only get a three-year warranty, where some other alarms offer five or ten years. If neither of these is a dealbreaker, you can stay safe and save a little cash.
Key specs – Type: Optical; Battery type: 9V alkaline; Display: Red LED; Alarm volume: 85dB; Connectivity: N/A; Interconnected: No
6. FireAngel HT630 Heat Alarm: Best heat alarm
Price when reviewed: £25 | Check price at Amazon Smoke alarms play a key role in home protection, but they’re no good in the room where the most fires break out: the kitchen. Here you need a heat alarm, which responds to changes in temperature rather than changes in heat. The FireAngel HT630 is a good, affordable, well-regarded unit, backed by a ten-year warranty and powered by a sealed-in Lithium battery with a ten-year lifespan.
It combines FireAngel’s Thermistek sensor with a heat disk that’s designed to reflect directional heat from a fire onto the sensor, so that you get a faster reaction to an outbreak. And, like FireAngel’s Thermoptek-powered smoke alarms, it has a hush button you can push should it go off unnecessarily, sparing you an 85dB ear bashing. With no interconnectivity between alarms, you’ll need the pricier WHT-630Q to comply with Scottish law, but this gives you that essential extra layer of fire protection for the price of a pizza or a couple of cinema tickets.
Key specs – Type: Thermistek heat sensor; Battery type: Internal Lithium, 10-year lifespan; Display: Red LED; Alarm volume: 85dB; Connectivity: N/A; Interconnected: No