Twist the smoke alarm counterclockwise to remove it from the mounting bracket
If hardwired, turn off power at the circuit breaker first
Open the battery compartment
Remove the old battery
Insert the new battery, matching the positive and negative terminals
Close the battery compartment
Reattach the smoke alarm to the mounting bracket
Turn power back on if it was hardwired
Press the test button to confirm the alarm works
Replace the battery immediately if the low-battery chirp continues