5 critical smoke alarm maintenance checks to make during the coronavirus lockdown

With the country in lockdown and most of us stuck indoors all day, now is the ideal time to check and maintain your smoke alarms, including making sure you have enough of them in your home and they're in the right places.

But as well as regular maintenance checks, buying the right smoke alarm really matters. New Which? research reveals that some alarms sold online simply can't detect smoke and won't raise the alarm when you need them to.

Our most recent smoke alarm tests uncovered two smoke alarms bought from eBay - but also listed on AliExpress and Wish - that repeatedly failed to detect smoke in our tests.

Check out these two alarms and five other dangerously unreliable smoke alarms in our smoke alarm Don't Buy reviews.

Five smoke alarm maintenance checks to make in your home

1. Do you have enough smoke alarms in your home?

If you only have one smoke alarm in your home, that's unlikely to be enough, given that a fire could start almost anywhere. The bare minimum is one per floor, but the London Fire Brigade (LFB) suggests fitting a smoke alarm in every room where a fire could start.

2. Do you have the right types of smoke and heat alarms in your home?

Optical or photo-electric smoke alarms are usually best at detecting smoke from smouldering fires which take some time to get going. The best place for them would be living rooms, bedrooms, hallways and landings. Read more about optical smoke alarms.

Ionisation alarms are good at detecting smoke from fast-flaming fires and need to be quick to sound the alarm. Stairwells and upstairs landing are a good place to fit them. Just make sure they're not too close to the kitchen as they can be prone to false alarms caused by smoke from cooking. Read our ionisation smoke alarm reviews.

When it comes to detecting fires in the kitchen, go for a heat alarm. The benefit of a heat alarm is it will sense dramatic rises in temperature caused by a fire without being triggered by things such as smoke from cooking. Read our heat alarm reviews.

3. Do you regularly check your alarm to see if it still works?

Test your alarm weekly by pressing the test button - if the alarm sounds, you can feel confident it's still receiving power from either the battery or the mains. If nothing happens when you test it, you'll need to replace the alarm.

4. When did you last replace the battery in your smoke alarm?

If you have a smoke alarm with a replaceable battery, you'll need to replace the battery - usually the 9V variety but sometimes AA - every 12 months. The alarm will chirp periodically to let you know it needs a new battery.

5. Do you know when to replace your alarm?

Whatever kind of alarm you have (replaceable battery, sealed battery, mains powered), more regular chirps - around one every 30 seconds or so - mean the alarm has reached the end of its working life and will need to be replaced.

To help you to remember when to replace your smoke alarm, write when you bought it on the case of the alarm. By doing this, you will know when to replace the battery. And by checking how long the alarm is designed work for (five, seven or 10 years) you will be well set to replace it when the time comes.

Yet more dangerous smoke alarms bought from eBay sellers

For the third time in three years we have bought smoke alarms from eBay sellers that have failed to detect smoke in our lab tests.

Alarms which appeared to be identical to the two that have recently failed to detect smoke in our tests were also listed on AliExpress and Wish. While many of these dangerous alarms are unbranded, it's the physical characteristics that give them away.

Dangerous smoke alarm 1 - Digoo DG-SA10, £5

This cheap and unreliable alarm failed to sound in seven of our eight smoke detection tests. The consequences of this happening in your home don't bear thinking about and that's why we've made it a Don't Buy.

The alarm we tested was branded as the Digoo DG-SA10, but you'll find identical-looking alarms that are unbranded. So, identify this one by its appearance - if you see an alarm with a case identical to this one, our best advice is to steer well clear of it.

Dangerous smoke alarm 2 - Unbranded WiFi smoke alarm, £28

This smart alarm was anything but smart in our tests. It failed to detect smoke in four of our eight lab smoke detection tests and when it did sound, it took far too long to do so. That's why we had no hesitation in making this dangerous alarm a Don't Buy.

We bought both the above alarms from sellers on eBay, but identical-looking alarms were also available on AliExpress and Wish when we checked. We found no listings for alarms that had failed our tests when we checked Amazon.

Online marketplaces continue to sell dangerous smoke alarms

This isn't the first time cheap smoke alarms bought through online marketplaces have failed to sound in our tests.

In 2018, we tested the unbranded and dangerous SS-168 smoke alarm bought from an eBay seller which failed to sound in seven of eight lab tests. And in 2019 we found four more cheap alarms that will fail to sound when you need them.

On each occasion, eBay and the other online marketplaces, which were allowing these alarms to be sold, removed the listings from their sites along with hundreds of other listings for identical-looking alarms.

80 dangerous smoke alarm listings removed following Which? investigation

Following our latest investigation, eBay removed the listings for the two dangerous alarms from its site. It also took down listings for another 39 alarms that appeared to be identical to the newly tested and dangerous Digoo DG-SA10.

We found 13 listings for identical alarms on AliExpress which were all removed when we flagged them to the site. There were 26 listings for alarms that looked the same on Wish, which were all removed from the site when we contacted them.

We contacted eBay about the dangerous smoke alarms being sold through its site. An eBay spokesperson told us that any items that breach its product safety policy will be removed and enforcement action taken against the sellers. They went on to say that if a seller is found to be listing an item that has been recalled or may be unsafe, eBay will request they issue a safety warning and a refund to all buyers.

An AliExpress spokesperson told us: 'After notification, we took prompt action and removed third-party product listings identified to be in violation of our listing policy. We take product safety very seriously and work relentlessly to ensure that consumers are protected on our platform. We have strict platform rules that require all third-party sellers to comply with all applicable local laws and regulations. We will continue to take action against sellers which violate our terms of use.'

A spokesperson for Wish told us: 'Whilst the vast majority of the products on our platform are well received by our customers, there are rare instances where products fall foul of our basic quality standards. In such cases, we act quickly to remove those products and take any necessary action to ensure they do not appear again.'

Making online market places safer - our four key asks

To protect consumers from buying unsafe products, such as the smoke alarms featured here and the other dangerous products Which? testing has revealed being sold online, significant regulatory improvements need to be made to ensure that we're protected when buying from online marketplaces.

• Sell safe products - Online marketplaces should be required to ensure that consumer products offered for sale by sellers on their sites are safe.
• Clarity on what to do when products are found to be unsafe - The steps online marketplaces need to take when unsafe products are identified should be clarified.
• Greater enforcement powers - Enforcement officers, such as trading standards departments and the Office for Product Safety and Standards (OPSS), should have the appropriate powers, resources, investigatory skills and intelligence to police online marketplaces, and the supply networks that underpin them.
• Transparency for consumers - There should be greater transparency obligations so that consumers are clear who they are buying from.

To find the best smoke alarm for you, check out our smoke alarm Best Buy reviews.

Coronavirus:Read the latest advice from Which?