Which? reveals shock difference in smoke alarm response times

A Which? investigation has highlighted a wide variance in the time it takes some of the UK’s most popular smoke alarms to sound, with one alarm failing to go off at all.

In a series of four controlled fire tests of 15 smoke alarms, the consumer champion discovered that smoke alarms meeting the British Standard can still pass the official tests and receive the Kitemark, despite hugely different response times.

Worryingly, one of the two samples of a Devolo alarm tested failed to sound at all in two of the fire tests performed. Which? is now listing the Devolo Home Control Smoke Detector as a ‘Don’t Buy’ as a result.

The Which? investigation covered four types of fire tests, these were smouldering wood, solvent, plastic and cotton fires. Concerningly, a pattern of British Standard approved alarms having wildly varying response times was repeated across all types of tests.

In our fire tests involving smouldering wood, two approved examples of the First alert SA300Q and the EI Electronics Ei3500S took more than nine minutes to trigger. While the fastest alarm we tested in this category, the Nest Protect Smoke+ Carbon Monoxide Alarm, was more than four minutes quicker to sound with the same type of fire.

But according to the official safety testing method – which measures the amount and thickness of smoke that is required to trigger the alarm – these response times are fine and all of the products we tested meet the BS EN 14604 standard.

The safety consequences of a slow-to-sound fire alarm could be significant. In the event of a house-fire, every moment may count when it comes to getting you and your family to safety.

Which? wants to see a new, tougher standard that only rewards models that sound more quickly.

Which’s? findings have been passed on to Trading Standards. We have also raised our response-time concerns with BSI (formerly the British Standards Institution), the business standards company responsible for issuing the smoke alarms test standard. It said: ‘The standard covers ionisation and optical alarms, and the test fires ensure that whichever type is used, the alarm gives adequate warning when there is a real fire.’ It also said a new smoke alarms standard is being drafted.

Alex Neill, Which? Managing Director of Home Products and Services, said

“People will be surprised to see such a big variation in response times from alarms that are currently classed as being safe and which pass the standard. We want to see stricter testing criteria because every minute counts in a fire.

“Anyone wanting to find out more about smoke alarm performance can visit the Which? website to compare the full test results.


Notes to Editors

Price Type Response time, wood fire (minutes)
Nest Protect 2nd Generation Smoke + Carbon Monoxide Alarm £      100 Smart Optical


Devolo Home Control Smoke Detector £50/£160* Smart Optical


Fire Angel ST-622 £        26 Optical


Fire Angel ST-620Q £        17 Optical


First Alert SA700LQ £        19 Optical


First Alert SA720CE £        19 Optical


Fire Angel ST-625 £        12 Optical


First Alert SA200Q £        11 Ionisation


Kidde 10Y29 £        16 Optical


Kidde i9040 £          9 Ionisation


Kidde i9060 £        13 Ionisation


Kidde i9080 £        13 Ionisation


EI Electronics Ei100B £          9 Ionisation


EI Electronics Ei3500S £        16 Ionisation


First Alert SA300Q £        13 Ionisation


  • The alarm costs £50 but you will also need a £110 Devolo Home Control central unit to link to your alarm
  • Which? is calling for urgent changes to the PRODUCT SAFETY regime including:
  • A new national body to take responsibility for product safety and recalls, which has the resources and expertise to identify dangerous goods and to make sure they are removed from people’s homes.
  • A single, reliable and well-publicised website – acting as a ‘one-stop-shop’ – to provide authoritative information and advice when dangerous products are identified or recalls are required.

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