Why Do Fire Alarms Go Off With No Smoke?

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In the United States, smoke alarms in buildings are mandatory. They detect the presence of smoke. Certain factors other than smoke can set off your alarm periodically. Test and maintain your smoke alarm to maintain efficiency.


Steam and vapour from cooking food can set off the alarm. If your smoke alarm is located close to air heating systems, air blowing from the unit can set off the alarm. Steam from showers and sinks may also trick the alarm into believing there is smoke in your house.


Smoke alarms are extremely sensitive. Insects crawling into compartments can set off the alarm. Cobwebs can also set off the alarm.

Testing and Maintenance

Test your smoke alarms at least once a month. Most smoke alarms have a test button you simply press to hear the high pitched sound. Check the batteries and replace them when necessary. Most smoke alarms produce a beeping sounding warning you that the batteries are low. Take down your smoke alarm and vacuum it to remove insects, dust and other particles.

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