The best smoke alarms for 2025, tested by us

Get early warning of a fire with the best smoke alarms, including smart smoke alarms and stand-alone units
Fitting smoke alarms isn’t just a no-brainer, but one of the most important steps you can take to protect your life, your family and your property. Smoke alarms can give you early warning of a fire before it spreads, so you can get everyone safely out of the house and call 999.
“Working smoke alarms save lives” says the National Fire Chiefs Council (NFCC). “Latest fire statistics in England show you are around 12 times more likely to die in a fire if you do not have a working smoke alarm in your home.”
What’s more, you’re going to need more than one. “It’s important that you install at least one smoke alarm on each level of your home and test them regularly.” And if you’ve got old alarms, you should think about replacing them. “All smoke alarms, no matter how they are powered, have sensors that deteriorate over time, rendering them less effective in detecting fires” says the NFCC spokesperson. “Make sure you replace old alarms.”
But which smoke alarms should you fit? While it’s easier than ever to find a good alarm at an affordable price, there are some older and less effective options out there. What’s more, you might want to invest in a connected alarm system or smart smoke alarms. Interlinked alarms are now required by law in private rented homes in Wales and all homes in Scotland. “If they aren’t required by law in your home,” says the NFCC, “they can be a great option to consider, as when one activates, they all sound.”
With so many options, you may be looking for some guidance – and that’s where I can help. I’ve spent the last few weeks retesting some of our favourite smoke alarms, and testing a selection of new ones. Below, you’ll find my pick of the best smoke alarms to buy. You’ll also find a short, at a glance, list of recommendations. And, if you’d like to know more about choosing a smoke alarm, check out the buying guide at the bottom of this page.
Best smoke alarms: At a glance | ||
---|---|---|
Best smart smoke and carbon monoxide alarm | Google Nest Protect | Check price at Amazon |
Best value smoke alarm | X-Sense Link+ Pro | Check price at Amazon |
Best basic smoke alarm | Kidde DY29 | Check price at Amazon |
Best interconnected smoke alarm | Cavius CV2106 | Check price at CPC Farnell |
How we test smoke alarms
We test smoke alarms using an aerosol tester, sprayed at the alarm from a distance of 50cm for three seconds, then timing how long the alarm takes to respond. We then measure the noise output of the siren using a smartphone sound meter, and take a look at any controls, screens and indicators to see how clear and effective these are.
With smart, Wi-Fi or interlinked options, we set them up with the hub or network, then check that any smartphone app notifications or shared alarms work. If the alarm also detects Carbon Monoxide, we’ll test that with a separate spray. We also check the instructions and fittings to see how easy the alarm is to install, and where the alarm uses replaceable batteries, we see how simple these are to replace.
READ NEXT: Best carbon monoxide alarms
The best smoke alarms you can buy in 2025
1. Google Nest Protect: Best smart smoke and carbon monoxide alarm
Price when reviewed: £91 | Check price at Amazon
- Great for… ease of use, clear alerts and smart features
- Not so great for… lack of deeper Google and Nest integration
The original Nest Protect helped define the whole smart alarm category, and while the second generation version is itself now long in the tooth, it’s still the best smart alarm around. It’s a fairly large but stylish unit with a large central button for testing and muting the alarm – although you may not need to use it, as you can do both from within the Nest app.
It uses an advanced split-spectrum optical sensor to spot the large smoke particles formed by smouldering fires and the smaller particles created by fast-flaring blazes. It also incorporates temperature and humidity sensors, ambient light and motion sensors, and it has a chemical CO sensor that lasts ten years.
In my tests, the Nest Protect wasn’t the fastest smoke detector, taking 7.12 seconds to register the test spray blast. However, the test spray isn’t designed to make full use of the split spectrum sensor. The alarm is loud at 98.7dBA, and you get alerts through your phone, plus a voice alarm from the Nest Protect itself.
This first warns you it has detected smoke, then goes into a full alarm as smoke levels rise. I also liked the Nest Protect’s useful bonus feature: a low glow when it detects motion to help guide your way in darkness. I’m not so keen on the lack of integration with Google’s Nest audio products or its reliance on six AA Lithium batteries, which last up to five years. Otherwise, though, this is still the smart alarm to beat.
Read our full Google Nest Protect 2nd Generation review
Key specs – Sensor: Split-spectrum optical; Battery type and predicted battery lifespan: 6 x AA lithium, 5 years; Display: LED ring indicator; Alarm volume (stated): 85dBA; Connectivity: 802.11n Wi-Fi; Interconnected: Yes
2. X-Sense Link+ Pro Smoke Alarm with Base Station: Best budget smart smoke alarm system
Price when reviewed: £70 | Check price at Amazon
- Great for… loud alerts across the home, easy to use, very affordable
- Not so great for… app not as polished or flexible as Nest Protect
Given that a single Nest Protect alarm will cost you close to £100, this X-Sense smart alarm bundle is something of a bargain. Roughly £80 buys you three smoke alarms plus a wireless Base Station, giving you enough early fire detection to cover the average UK home. The base station requires a 2.4GHz Wi-Fi network to operate, connecting through the X-Sense smartphone app and free X-Sense services in the cloud. I had the Base Station and three smoke alarms up and running within fifteen minutes, although you will also need to install them on the ceiling using the supplied backplates.
When one alarm goes off, all connected alarms spread the alert. And with voice alerts plus a 99.1dBA siren, you’re not likely to miss it, especially with an app notification and email alert following close behind. Handily, you can test and hush all alarms from the app, or by pressing the button on any one alarm.
The only downside is that the alarm isn’t super-speedy, taking 7.51 seconds to sound after my test spray barrage. The Link+ Pro bundle doesn’t quite have the smarts and polish of the Nest Protect – you’re stuck with presets and can’t add your own room names in the app – but it’s a much cheaper way to protect your home.
Read the full X-Sense Link+ Pro Smoke Alarm with Base Station review
Key specs – Sensor: Photoelectric; Battery type and predicted battery lifespan: 3V CR123A lithium, 5 years; Display: LED ring indicator; Alarm volume (stated): 85dB; Connectivity: 802.11n Wi-Fi; Interconnected: Yes
3. Aqara SD-S01E Smoke Detector: Best smoke alarm for smart home automation
Price when reviewed: £45 | Check price at Amazon
- Great for… home automation fans willing to invest in further Aqara kit
- Not so great for… simple Alexa or Google Home setups where you don’t want an additional hub
The Aqara SD-S01E takes a different tack to Wi-Fi connected smoke alarms by using the Zigbee wireless protocol. Designed for light bulbs, sensors and other Internet of Things (IoT) devices, it’s more stable and energy-efficient, but requires the use of a separate Zigbee hub. In the case of the SD-SO1E, this means Aqara’s own Hub M2 or M3 products, as it doesn’t work with third-party Zigbee hubs like those built into Amazon’s recent Echo speakers.
This makes the Aqara an expensive proposition – the Hub M3 costs around £100 – but the upside is more potential for clever smart home automations, especially if you have other Aqara security products or compatible smart lighting. You also get alerts through the Aqara Home app, and when one alarm goes off you’ll get it repeated through other connected alarms as well as a speaker in the hub.
The alarm is reasonably sensitive, sounding within 7.25 seconds of a blast from the test spray, and loud at 93.7dBA. I had some issues getting the Hub set up, and – despite being Matter-compliant – I couldn’t get it working with Google Home. Otherwise, though, this is a solid buy if you want a smoke alarm to work with your existing Zigbee, Alexa or Homekit setup.
Read the full Aqara SD-S01E review
Key specs – Sensor: Photoelectric; Battery type and predicted battery lifespan: 3V CR17450 lithium, 10 years; Display: LED indicator; Alarm volume (stated): 85dB; Connectivity: Zigbee; Interconnected: Yes
4. Kidde DY29 Smoke Alarm with Hush: Best basic smoke alarm
Price when reviewed: £12 | Check price at Amazon
- Great for… rapid response alarm, easy to hush, low price
- Not so great for… only basic features
If all you want is a good, basic smoke alarm, look no further. The Kidde DY29 is compact, at just 10cm in diameter, and easy to fit with a simple mounting bracket. It runs off a single 9V battery, which needs replacing roughly every year, and it has a chunky button on the surface that both hushes and tests the alarm. Hushing the alarm will keep it quiet for nine minutes while you clear away the smoke, after which the alarm resets. It’s all very simple.
It’s effective, too. In my tests, it was the fastest alarm to trigger, sounding in just 2.44 seconds after a three-second blast of test spray. There’s no problem with the volume either, with the DY29 dishing out a piercing 97.6dBA racket. As long as you don’t need a connected smoke alarm and you’re happy to replace the battery annually, you don’t need to spend any more.
Key specs – Sensor: Photoelectric; Battery type and predicted battery lifespan: 9V PP3 Alkaline, 1 year; Display: LED indicator; Alarm volume (stated): 85dBA; Connectivity: None; Interconnected: No
5. X-Sense SC07-WX Wi-Fi Carbon Monoxide and Smoke Alarm: Best combi smoke alarm
Price when reviewed: £83 | Check price at Amazon
- Great for… CO and fire protection in one package, optional smart features
- Not so great for… comparatively bulky
This X-Sense smoke alarm might be somewhat chunky, at 14.6cm in diameter and 5cm thick, but it packs in both a smoke detector and a chemical carbon monoxide detector, plus a basic one-line LCD screen. This gives you the current CO reading and test results when you press the test/silence button. You’ll need plenty of space for the mounting bracket, which is even larger than the unit itself, but it’s easy to fit and the unit locks securely into place.
The SC07-WX also has built-in Wi-Fi, giving you the same alerts and smart features as the X-Sense Link Pro+ once connected to the X-Sense app. Most importantly, it works well as both a smoke and CO alarm, registering smoke within 6.6 seconds and a carbon monoxide test spray within 4 seconds, and dishing out a loud 98.8dBA alarm with accompanying red flashing light. It runs from a single 3V Lithium battery (CR123A), designed to last five years of the unit’s ten-year lifespan. It’s a great option for rooms with a fuel-burning appliance where you could do with an all-in-one alarm.
Key specs – Sensor: Photoelectric; Battery type and predicted battery lifespan: 3V CR123A lithium, 5 years; Display: LED indicator, backlit LCD display; Alarm volume (stated): 85dBA; Connectivity: 802.11n Wi-Fi; Interconnected: Yes
6. Cavius CV2106: Best interconnected smoke alarm
Price when reviewed: £35 | Check price at CPC Farnell
- Great for… fast fire detection
- Not so great for… not much. It’s simple and effective
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. In tests with a hair dryer used below the detector, the alarm took less than ten seconds to go off. 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
7. Kidde K2007 Mini Smoke Alarm: Best micro smoke alarm
Price when reviewed: £25 | Check price at Screwfix
- Great for… small rooms
- Not so great for… no notes here
At just 4cm across the Kidde K2007 is tiny, making it a great option for boats, caravans and other cramped spaces where you might not want to fit a larger smoke alarm. It twists and clicks into the bundled two-hole mounting plate, and runs on a sealed-in Lithium battery that should last the unit’s entire ten-year lifespan. The top doubles as a test button and as a hush button for silencing false alarms.
Despite its smaller stature, I’ve got no complaints about the K2007 as an alarm. It registered the test spray in under seven seconds, and can put out an ear-splitting 101.4dBA noise when triggered. Now even where you’re short of ceiling space, there’s no excuse for not having a good smoke alarm.
Key specs – Sensor: Optical; Battery type and predicted battery lifespan: Sealed Lithium, 10 years; Display: LED indicator; Alarm volume (stated): 85dB at 3m; Connectivity: None; Interconnected: No
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 older ionisation alarms, a radioactive isotope (far too small to cause any harm) causes ionisation in the air within the smoke alarm, and these ionised air particles react in the presence of smoke particles, triggering the alarm.
The second type uses an optical sensor, which detects smoke as it enters the sensor chamber, setting the alarm off. These are less prone to false alarms than the ionisation type, and so have become more common. They aren’t always as sensitive to other types of fast-flaring fire, but the difference isn’t huge. What’s more, many fire services now discourage the use of ionisation alarms, and many have been discontinued.
For kitchen, garage and 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 – usually 58°C. Heat alarms are slower to respond than smoke alarms, but also less prone to going off when burning toast or grilling sausages.
Different makes and models may have different sampling rates for their optical sensors, checking the air every six to ten seconds, then increasing the rate if any smoke is detected. Some will also feature voice alarms or strobing lights. However, all alarms sold in the UK must meet the BS EN14604:2005 standard, which specifies the requirements, tests and performance criteria for optical and ionisation smoke alarms.
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What about the battery?
While some smoke alarms still rely on an old-school alkaline 9V battery, the trend is now towards smoke alarms with long-life lithium batteries, which typically last between five and ten years. Ten years is usually seen as the operational life of a smoke alarm, and in Scotland ten-year battery life is a legal requirement. There’s nothing wrong with a 9V battery-powered alarm, provided you replace the battery every year or are happy to get hit with a 2am wake-up call when the battery alert commences its infernal beeping.
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, all alarms in the home do the same. This usually means buying one or more interlinked alarms, which connect over a dedicated RF connection. 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.
Alternatively, manufacturers are now offering smart smoke alarms, which either connect to a central Hub or direct to your Wi-Fi router. These can also spread the alarm across multiple units, as well as alert you through your smartphone.