Alarm Testing Schedule: How Often to Test Smoke & CO Detectors

Smoke alarms and carbon monoxide detectors only protect you if they work. Most failures come down to one thing: nobody tests them. This schedule keeps both systems reliable with almost no effort.

If your alarms are older or you’re not sure which type you have, check Replacing Smoke Detectors before you build your routine.

1. Monthly Testing (Smoke & CO Alarms)

Do this on the same day each month—first day, last day, or a date you’ll remember.

• Press and hold the test button until the alarm sounds
• Ensure the sound is loud, clear, and not distorted
• Repeat for all alarms on every level of the home

Interconnected alarms should all sound at once. If they don’t, see Interconnected Alarm Benefits.

2. Quarterly Checks (Every 3 Months)

Every few months, do a quick visual inspection:

• Look for dust buildup on vents
• Make sure the alarm isn’t painted over
• Check that it’s still firmly mounted
• Confirm no furniture or décor blocks airflow

If you’re cleaning, follow the same steps in Fire Alarm Maintenance.

3. Twice-Yearly Cleaning

Every six months—usually tied to daylight savings time—clean every alarm:

• Vacuum around the vents with a soft brush
• Remove cobwebs near ceilings
• Wipe the outer casing with a dry cloth (no chemicals)

4. Annual Battery Replacement (If Not Sealed)

If your alarms use replaceable batteries:

• Swap every battery once per year
• Use quality batteries to avoid corrosion
• Update the replacement date marked on the alarm

If false alarms increase after battery replacement, read Reducing False Smoke Alarms.

5. Full Alarm Replacement at 10 Years

Smoke alarm sensors wear out. The 10-year rule applies to:

• Photoelectric alarms
• Ionization alarms
• Dual-sensor alarms
• Hardwired systems with battery backup

CO detectors usually last 7–10 years depending on the model.

6. After Any False Alarm or “Trouble Beep”

Treat unusual alarm behavior as a prompt to inspect the unit:

• Check for dust around the sensor
• Replace batteries if applicable
• Review placement—heat, steam, or drafts may be triggering it

If the problems persist, the detector is likely at end of life—replace it.

7. Quick Alarm Testing & Maintenance Schedule

• Monthly: Test all smoke and CO alarms
• Every 3 months: Visual inspection and airflow check
• Every 6 months: Clean vents and surrounding areas
• Yearly: Replace batteries (if not sealed)
• Every 7–10 years: Replace CO detectors
• Every 10 years: Replace smoke alarms

This schedule takes minutes per year and ensures your alarms work when you need them—not years after they quietly failed.