Smoke alarms

We tested 12 models to see which respond fastest to smoke.

Smoke alarm on ceiling.

Our test was based on the UL217 standard for smoke alarms.

We've tested 12 smoke alarms.

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Overall score

Overall score is based on smouldering and flaming fire sensitivity.

How we test

Photograph of a lab technician testing smoke alarms.

Multiple alarms were placed in our “smoke-sensitivity chamber”. Smoke was introduced from a “smoke box”, which contained the burning or smouldering source, so the level of smoke increased steadily until the alarm was triggered.

We generated smoke from flaming wood, flaming oil, smouldering wood chips, and smouldering upholstery foam. We also used burning toast and a frying hamburger pattie to see how the alarms responded to “nuisance alarm” sources.

We tested three samples of each alarm with each smoke source.

Measuring sensitivity

Our results show how the alarms responded compared to control sensors in the chamber for flaming and smouldering smoke sources. A “Good” or “OK” response meant the alarm sounded quickly enough to alert you to danger. Alarms with a “Poor” response took significantly longer to sound, while “Extreme” sensitivity meant the alarm sounded so quickly they are more likely to issue false alarms.

Ease of use

We also assessed the quality of the supplied instructions and how easy an alarm was to install. This doesn’t contribute to our overall score.

Female hands opening smoke detector to change battery.

Smoke alarms guide

Before you buy, check out our buying guide.

Read the guide