Don't Buy this carbon monoxide (CO) alarm – it failed to sound in 13 of our carbon monoxide detection tests

Bought from an online marketplace, this is yet another cheap and unbranded carbon monoxide (CO) alarm that you simply can’t rely on to detect CO. We’ve made it a Don’t Buy, as our test results show that it's unreliable when it comes to detecting CO.

UnbrandedCarbon monoxide alarm 9

Name: Unbranded Carbon monoxide alarm 9
Brand: Unbranded
SKU: WH18639-0032-01

£15.79Typical price

Test result

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Whatever we tested this alarm, the result was the same - carbon monoxide (CO) wasn’t detected and the alarm, at least most of the time, failed to sound. As CO levels grew, the alarm remained silent. When we surrounded it with a horrifyingly high level of CO, the gas was detected. However, afterwards, the alarms tested failed to detect lower, but still incredibly dangerous, levels of CO. And when it did sound, it was far too quiet, registering only 68 and 62 decibels (dB), when it should have hit 85dB initially, then 82dB after four minutes. So, this dangerous alarm is a clear Don’t Buy.

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Aug 2024Last checked by Which?
Jun 2023First reviewed by Which?
Jan 2023Released

The overall Which? test score is made up of the following star ratings, all determined by our rigorous lab tests.

How we test carbon monoxide detectors

27 Feb 2024

Carbon monoxide (CO) detection

How we test carbon monoxide (co) detection

Five stars means that the CO alarm detected CO in every one of our tests. One star means that the alarm failed to detect CO in one or more of our CO detection tests. We test each carbon monoxide (CO) alarm more than 30 times to see whether it can detect the deadly gas. We test with low concentrations of CO and higher concentrations. We also test with a catastrophically high concentration of the gas. We check whether the alarms respond in time and whether after detecting CO, they can go on to continue to detect the gas.

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UnbrandedCarbon monoxide alarm 9

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