How Often Should Carbon Monoxide Alarms Be Replaced?
By JC Pacific Corp Published 2026-09-01 Last professionally reviewed: September 2026
Carbon monoxide alarms should be replaced according to the manufacturer's end-of-life instructions, which may vary by model. Replace any device that is expired, damaged, malfunctioning, or unable to pass its test.
Why is carbon monoxide dangerous?
Carbon monoxide is colorless and odorless. Exposure can cause:
- Headache
- Dizziness
- Nausea
- Weakness
- Confusion
- Loss of consciousness
- Death
What should you do if the alarm sounds?
- Move everyone to fresh air
- Call 911 from a safe location
- Follow fire-department instructions
- Do not assume it is a false alarm
- Do not reenter until authorized
- Have fuel-burning systems evaluated
What maintenance is required?
- Test devices as directed
- Check manufacture and replacement dates
- Keep alarms unobstructed
- Replace batteries according to instructions
- Never disable an alarm
- Use compatible equipment
- Maintain fuel-burning appliances
Frequently Asked Questions
Is a smoke alarm also a carbon monoxide alarm?
Only if it is a listed combination unit.
Can a carbon monoxide alarm detect a gas leak?
Not necessarily. Combustible-gas detection is different.
Do all-electric homes need carbon monoxide alarms?
Requirements depend on the property's features and applicable code.
Educational information
This content is for general educational purposes and is not construction, engineering, electrical, plumbing, pest-control, insurance, legal, environmental, fire-safety, or emergency advice. Maintenance needs vary by property, age, construction, climate, location, and condition. Work involving electricity, gas, roofing, structural systems, pests, hazardous materials, or permits should be handled by appropriately licensed professionals. If you smell gas, see fire, observe electrical arcing, discover a major leak, or believe a structure may be unsafe, leave the affected area when appropriate and contact emergency services or the responsible utility. Do not attempt a repair beyond your training.
Next step: Record every alarm's manufacture date, model, battery type, and replacement date.
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A note on these California home-maintenance guides: These articles provide general, educational information about routine home maintenance, seasonal preparation, and life-safety systems for California homeowners. They are not construction, engineering, electrical, plumbing, pest-control, insurance, legal, environmental, fire-safety, or emergency advice, and they do not create a contractor, inspector, engineer, insurer, attorney, or emergency-responder relationship with the brokerage. Maintenance needs vary by property, age, construction, climate, location, and condition. Work involving electricity, gas, roofing, structural systems, pests, hazardous materials, or permits should be handled by appropriately licensed professionals, and code, insurance, hazard, and local requirements must be checked against current official sources at publication time. Property DNA is only one supporting research service and is never a substitute for inspections, permit research, maintenance records, contractor evaluations, structural engineering, pest inspections, insurance, title review, or professional advice. In an emergency, leave the affected area when appropriate and contact emergency services or the responsible utility.