How often should you replace your smoke detector batteries?

This task protects people, not just the house. Do it on a schedule to make sure it gets done.

Staying on schedule matters beyond the repair bill: a consistent maintenance record is one of the factors in a home's Roots Home Health Score, and well-kept homes typically sell faster and closer to asking price.

How to do it

A smoke or CO detector with a dead battery protects no one, and the low chirp always seems to start at 3 a.m. Replacing batteries on a fixed yearly schedule keeps every alarm live.

1. Once a year (a good cue is a time change), replace the battery in every non-sealed detector.
2. Press and hold the test button afterward to confirm the alarm sounds.
3. Vacuum the vents while you're there to prevent dust false-alarms.
4. Note any unit that chirps again soon; the whole detector may be at end of life.

Alternatives & optional extras

• Long-life lithium batteries last years longer than alkaline and cut down the ladder trips.
• Sealed 10-year-battery detectors skip this task entirely; the whole unit is replaced at 10 years instead.

Time: 15 minutes · Typical cost: $10–$25 for batteries

If you skip it

A dead battery leaves a detector silent in a fire or CO event, removing the warning that gives people time to get out.

Other smoke & co detectors maintenance

• Test smoke and CO detectors — once a month
• Replace smoke and CO detector units — every 10 years

Related systems to keep on schedule

• Fire extinguisher — start with: check fire extinguisher gauge and condition, once a year
• Security system — start with: test security system and camera batteries, every 6 months