Tools & materials
- New 9V or AA batteries (check the alarm)
- Sturdy step ladder
- Broom handle for testing high ceilings
Step by step
- Step 1
Twist the alarm counterclockwise off its base. Hardwired alarms will hang by a plug, which is normal.
- Step 2
Remove the old battery and install the new one, matching the + and – marks.
- Step 3
Twist the alarm back onto the base until it locks.
- Step 4
Press and hold the TEST button until the alarm sounds loudly.
- Step 5
Check the manufacture date on the back. Replace smoke alarms 10 years after that date, and CO alarms per the label (usually 7–10 years).
- Step 6
If it keeps chirping, press and hold TEST for 15 seconds to clear the error.
When to stop and call ProFix
If you see any of these, stop and call us:
- The hardwired alarm still chirps or won't power up
- You need alarms added in bedrooms or interconnected (rentals often require this)
- The alarms are over 10 years old across the home
Not in the mood to DIY? A ProFix pro can handle it for you in Chicago Metro and Dallas–Fort Worth, with a written price before work starts.
Related guides
These guides are general information for simple repairs. You're responsible for your own safety and for following local codes and your lease or HOA rules. When in doubt, stop and call a licensed professional. All DIY guides