We test smoke and heat alarms to British test standards in lab conditions to find the alarms that will sound every time you need them to.

FireAngel ST-622 how to change battery

If anyone in your family might struggle to hear it - if, say, they have a hearing impairment, or they're a particularly heavy sleeper - then you may want to set up your alarms to account for that.

It's best to use disposable batteries in smoke and heat alarms. Rechargeable ones lose their charge more quickly, so they'll need to be replaced more frequently.

fireangel st-622

We regularly revisit the smoke alarms and heat alarms on sale to see if there are any more popular models that need testing – and when we find them, we do.

If a year hasn't passed and your alarm is chirping, this is another sign that the batteries need replacing, as measuring their lifespan is not an exact science.

fireangel st-620

When buying smoke alarms, heat alarms and carbon monoxide alarms, our research shows that it's best to avoid cheap, unbranded products from online marketplaces, as all those we tested went on to fail some or all of our detection tests.

FireAngel Heat Alarm

Need to know Comes with a 9V back-up battery,  can be connected to more than 20 Kidde alarms, suitable for homes in Scotland, six-year warranty

Smoke alarm tests are carried out to extracts from the smoke alarm devices standard BS EN 14604. Heat alarm tests are carried out to elements of the BS EN 5446-2:2003 standard, fire detection and fire alarm devices for dwellings.

Need to know Smoke and CO alarm, smart (wi-fi connected), your phone sounds when it detects smoke, 10-year sensor lifetime

Need to know 10-year battery, 12 alarms can be connected in one system, large test/hush button, suitable for homes in Scotland

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FireAngel Sleep Easy

For a product this critical, and for the sake of safety and convenience, it's best to use a disposable battery that will last for a long time.

To get the best response from your alarm, it should go in the centre of the ceiling, away from obstructions or dead spaces, such as where the walls and ceiling join. You should be able to hear it clearly across the whole space it's intended to cover, so bear this in mind as you look around your home and consider the risks.

Need to know Comes with a 10-year back-up battery, links to other Aico alarms, 10-year guarantee, suitable for homes in Scotland

Need to know Interlinkable and suitable for homes in Scotland, mains powered with a sealed back-up battery, 10-year guarantee

Fire Angel Smoke Alarm

When an alarm of any design – mains, sealed battery, replaceable battery – chirps, it can also mean it's at the end of its working life, which is usually 10 years. So if your alarm is chirping and is around 10 years old, it's time to get a new one.

It's a good idea to install batteries before attaching a new alarm to your ceiling. When you need to change them, the cover of the alarm will flip down to allow you to access the battery compartment.

Dates tested: June 2021 and June 2022. Page last checked: October 2024. We are not able to show every retailer and cheaper prices may be available.

A smoke alarm will need to be installed in the room you use most and you need to install an interlinked heat alarm in the kitchen. The new regulations also require interlinked smoke alarms to be fitted in all hallways and landings in homes in Scotland. These should be mains powered or come with a sealed battery rather than with replaceable batteries.

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A continuous sound coming from your smoke or heat alarm might indicate that it has become damaged, or the sound could indicate that it has developed a fault. In any case, if an alarm emits a continuous sound that isn't the very noisy sound of the alarm triggering, replace it as soon as you can.

fireangel st-750 review

Need to know Contains smoke and heat alarm sensors, can be linked with other related alarms, comes with a back-up 10-year battery

FireAngel battery replacement

Date tested: June 2018, 2019, 2020, 2021, 2022 and 2024. Page last checked: October 2024. We are not able to show every retailer and cheaper prices may be available.

If your smoke alarm or heat alarm is chirping intermittently and the alarm uses replaceable batteries, this would be a sign that the batteries need to be replaced.

This is likely to be an annual job if you have a smoke or heat alarm powered by disposable batteries, so make a point of doing this every year.

Buying the right smoke alarm could be one of your best decisions – it won't cost the earth to do this, but it could save your life. The Don't Buy alarms featured in the two photos here are to be avoided as none were able to detect smoke reliably in our tests, and in many cases they failed to sound in any of our eight smoke detection tests.

Smoke alarms need to sound quickly when they detect smoke – and heat alarms should be prompt to alert you when they sense heat rising.

All homes in Scotland need to have interlinked smoke and heat alarms installed. Homes that have a fuel-burning appliance, such as a boiler, open fire or log burner, will also need to have a carbon monoxide (CO) alarm installed in the room the appliance is in, although the CO alarm doesn’t need to be interlinked.

Our research shows that you can find a quick-to-sound, reliable smoke or heat alarm for around £20. But our tests have also uncovered some models that

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Eight of the nine Don't Buy smoke alarms were bought through online marketplaces and are unbranded, or came branded with the name of the online seller we bought them from. So if you have an alarm that looks like any of those featured, replace it with an alarm from a recognised brand available on the high street or through a well-known retailer's websites.

This can be inconvenient, while also posing a safety risk, if the alarm is without batteries while the rechargeables are being charged.

Need to know 10-year battery, seven-year warranty, interlinkable with up to 15 other alarms, suitable for homes in Scotland

Need to know 10-year battery, smart (wi-fi connected), alerts will sound on your phone when the alarm sounds, can't be linked to other alarms and not suitable for homes in Scotland

We put smoke alarms and heat alarms through rigorous tests in accordance with the British Standard to find the best and safest for your home.