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How Long Do Smoke Detectors Last?

Replace your smoke alarm batteries

According to the U.S Fire Administration, smoke detectors usually last about 10 years.

This is why Phoenix city ordinance G-5898-2014, section 1103.8.3.1 4 (titled “Smoke Alarm Replacement) says, “Smoke alarm shall not remain in service longer than 10 years from the date of manufacture.”

So, what exactly happens if you don’t replace the detector after 10 years?

Well, the detector is less likely to sound the alarm during a fire because:

  • The detector’s sensitivity to smoke will be lower.
  • There’s about a 1/3 chance the detector will be nonfunctional. According to the National Center for Healthy Housing, “Eight to ten years after the installation of these smoke alarms…30% were present but nonfunctional.”


“But I just tested my smoke detector and it’s working fine!”

Here’s the thing: The test button just confirms that the battery, electronics, and alert system are working. But NOT the actual smoke sensor.

You can test the smoke sensor by spraying an aerosol can over the smoke alarm (this will simulate smoke). If the alarm goes off, you should be fine. If not, check the batteries and try again. If it still won’t go off the sensor’s sensitivity has weakened and you should get a new smoke detector.

“How can I tell how old my smoke detector is?”

Depends on your smoke detector. You can find the manufacturer date by:

  • Taking off the cover and checking the inside faceplate
  • Removing the entire smoke detector and checking the back


“I keep having false alarms. Do I need a new smoke detector?”

Maybe. While some people think that alarms are a sign that you need a new detector, the problem could actually be dust build-up in the smoke detector’s sensor.

You see, ionization smoke detectors (the most common type) commonly mistake dust for smoke. So if too much dust gets in in the sensor chamber, the smoke detector will go off for no reason.

Since both new and old smoke detectors can have this problem, we wouldn’t say just random false alarms means you need a new smoke detector. But it certainly could indicate it.

Related article: Why Does My Smoke Detector Keep Going Off for No Reason?

Need someone to install a new smoke detector?

If you live in the Phoenix metro, we can help. Contact George Brazil for a smoke detector installation.

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