DIY guideSmoke and CO alarms

Replace a smoke or CO alarm

Read the date on the back, take the old alarm down, and put up and test a new one.

7 steps

Tap a step to watch it again.

Twist the alarm off its base and find the date it was made. Replace a smoke alarm 10 years after that date, and a CO alarm by the date its maker gives.
Get a new alarm that does the same job: smoke, CO or both in one, and battery or plug-in to match.
Unscrew the old base from the ceiling or wall. For a plug-in alarm, just unplug it.
Use a steady step ladder. Wires behind the base? Stop: that alarm is hard-wired.
Screw the new base where the old one was, with the screws from the box.
Pull out the battery tab, line the alarm up with its base and twist it on until it clicks.
Press and hold the test button until it sounds.
If wires run into the base, the alarm is hard-wired to the house. Leave it up and ask Handyman for an electrician.

Handyman says: Wired in? I'll find an electrician.

Free for every home. Handyman asks a few questions, then books a pro it trusts.