How do you test a smoke alarm and when should you replace it?
Short answer: Press and hold the test button once a month until the alarm sounds. The U.S. Fire Administration says to replace 9-volt batteries at least once a year and replace the whole alarm every 10 years from its manufacture date. A chirp every 30 or 60 seconds means a low battery. Chirping after a new battery means end of life.
How do you test a smoke alarm?
The U.S. Fire Administration (USFA) says to test every smoke alarm monthly. That applies to battery and hardwired alarms alike.
- Tell everyone in the home you are testing, since the alarm is loud.
- Use a sturdy step stool or ladder to reach the alarm.
- Press and hold the test button until the alarm sounds.
- If it stays silent or sounds weak, replace the battery and test again.
- If it still fails, replace the alarm.
- If your alarms are interconnected, check that every alarm sounds when you test one.
Follow the test steps in your alarm’s manual, because models differ.
How often should you change smoke alarm batteries?
It depends on the alarm type. The USFA gives this guidance:
| Alarm type | Battery | Replace whole alarm |
|---|---|---|
| 9-volt battery alarm | Replace at least once a year | Every 10 years |
| 10-year (long-life) lithium battery | Not replaceable | Per the manufacturer’s instructions |
| Hardwired with battery backup | Replace backup at least once a year | Every 10 years |
Many people pick a fixed yearly date for battery changes, such as a birthday. Any date works if you stick to it.
When should you replace a smoke alarm?
The USFA says to replace the entire smoke alarm every 10 years. The count starts at the manufacture date, not the day you installed it. The date is often printed on a label on the back, so take the alarm down and check.
Example: an alarm marked as made in 2016 is due for replacement in 2026 (2016 + 10). If you cannot find a date, a cautious rule of thumb is to replace the alarm.
Hardwired alarms should be installed only by a qualified electrician, according to the USFA.
Why is my smoke alarm chirping?
A short chirp is different from a fire alarm. The NFPA “Learn the sounds” tip sheet explains the patterns:
| Sound | Meaning | What to do |
|---|---|---|
| Continuous set of three loud beeps | Smoke or fire | Get out, call 9-1-1, stay out |
| Single chirp every 30 or 60 seconds | Low battery | Replace the battery |
| Chirping continues after a new battery | End of life | Replace the whole alarm |
| Continuous set of four loud beeps (CO alarm) | Carbon monoxide | Get outside, call 9-1-1, stay out |
Carbon monoxide alarms also chirp every 30 or 60 seconds for a low battery. Their end-of-life sounds vary by manufacturer, so check the manual. For where CO alarms belong, see carbon monoxide detector placement.
Where should smoke alarms be installed?
The USFA recommends alarms:
- On every level of the home, including the basement.
- Inside each bedroom and outside each sleeping area.
- On the ceiling or high on a wall, following the manufacturer’s instructions.
Smoke rises, which is why alarms go high. If an alarm keeps going off from cooking or shower steam, the USFA says to move the whole alarm several feet away from the kitchen or bathroom. Never remove the battery or disable the alarm to stop nuisance alarms.
Should smoke alarms be interconnected?
Yes, where possible. The USFA says to choose interconnected smoke alarms so that when one sounds, they all sound. With interconnection, an alarm on one floor can also sound on another floor.
Which type of smoke alarm is best?
There are two basic sensor types: ionization and photoelectric. The USFA recommends having both types in the home, or using dual-sensor alarms that contain both sensors.
Are there smoke alarms for deaf or hard of hearing people?
Yes. The USFA notes that alarms are made for people with hearing loss. These may use strobe lights, vibration, or both to alert someone who cannot hear a standard alarm.
Quick answers
How often should you test a smoke alarm? Once a month, using the test button. The USFA recommends this for every alarm.
How long do smoke alarms last? Replace them 10 years after the manufacture date printed on the alarm.
How often should I change a 9-volt smoke alarm battery? At least once a year, per the USFA. Replace it sooner if the alarm chirps.
Why does my smoke alarm chirp with a new battery? The NFPA tip sheet says chirping that continues after a battery change means the alarm has reached end of life. Replace the whole unit.
Do I need a smoke alarm in every bedroom? The USFA recommends alarms inside each bedroom, outside each sleeping area, and on every level.