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How Often Should You Replace a Carbon Monoxide Detector?

Carbon monoxide detectors often need replacement every 7 to 10 years depending on model. Learn how end-of-life alerts and battery chirps differ.

Direct answer

Many carbon monoxide detectors need replacement every 7 to 10 years, depending on the model. Use the date and manual on your exact unit. Replace it sooner if it reaches end of life, displays END or ERR, keeps chirping after a fresh battery, fails a test, is damaged, or has no readable date.

model label first; many CO alarms = 7 to 10 years before whole-unit replacement

CO detector replacement timing

Model label says 7 years

Replace at 7 years

CO sensors have model-specific life spans

Model label says 10 years

Replace at 10 years

Modern sealed units may last longer

END, ERR, or end-of-life chirp

Replace the detector

A battery swap will not renew the sensor

Low-battery chirp on active unit

Replace battery if allowed

Only applies before end of life

No readable date or manual

Replace

You cannot verify remaining sensor life

Detector situation	What to do	Why
Model label says 7 years	Replace at 7 years	CO sensors have model-specific life spans
Model label says 10 years	Replace at 10 years	Modern sealed units may last longer
END, ERR, or end-of-life chirp	Replace the detector	A battery swap will not renew the sensor
Low-battery chirp on active unit	Replace battery if allowed	Only applies before end of life
No readable date or manual	Replace	You cannot verify remaining sensor life

Do not guess from the battery alone

A CO detector's battery and sensor are different parts of the safety system. A battery may be replaceable, sealed, or still working while the sensor itself has reached end of life.

Check a CO detector

1Find the manufacture date, replace-by date, or model-specific service-life label.
2Check the manual for end-of-life chirp and display patterns.
3Test the detector with the test button on the schedule the manufacturer gives.
4Replace the whole detector at end of life, not just the battery.
5Install the replacement where the maker and local safety guidance recommend.

FAQ

Do carbon monoxide detectors expire?

Yes. CO sensors have a limited service life. Many modern units last 7 to 10 years depending on model, and the device label or manual should control the exact replacement date.

Can I just replace the battery in an old CO detector?

Only if the problem is a low battery and the unit is still within its service life. If the alarm is at end of life, replace the whole detector.

How is an end-of-life chirp different from a low-battery chirp?

Patterns vary by model. Check the manual, but repeated chirping after a fresh battery or a displayed END or ERR message often means the unit itself needs replacement.

Sources & method

We reviewed these references while writing this answer. Figures are estimates — confirm safety-critical work with a professional. Last updated June 7, 2026.