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Test and replace CO detectors
Trigger
Test monthly, replace every 5-7 years
Who does it
DIY
Est. time
10 min per unit
Est. cost
$20-40 per unit
Difficulty
●○○○○
Step by step
Press the test button and confirm the alarm sounds.
Check the expiration date printed on the unit - CO sensors degrade over time.
Install one on each level and near sleeping areas, at knee-to-chest height (CO mixes with air).
Replace batteries per manufacturer schedule.
If an alarm ever sounds, leave the house immediately and call for help from outside.
Video guide
How to Install Smoke and Carbon Monoxide Detectors - This Old House
Watch this guide
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