Carbon Monoxide Detector Beeping
If a carbon monoxide alarm sounds with a repeating pattern of loud beeps (often 4 beeps and a pause), treat it as an emergency: get everyone outside and call 911. A single chirp about once a minute usually means a low battery. Five chirps a minute on many models means the alarm has reached end of life. Check the label on your model to confirm.
Typical pro cost
$20 to $250
- Urgency
- Emergency if alarming
- DIY difficulty
- Easy
- Time to fix
- 5 to 30 minutes
- Prices
- US typical range
Last reviewed September 2026
Signs it's this problem
- Loud repeating beeps, often 4 beeps and a pause
- One chirp about every minute
- Several chirps each minute
- Display shows a CO level or an error code
- Alarm is 7 or more years old
Common causes
Carbon monoxide present
From a furnace, water heater, gas stove, fireplace, generator or a car running in an attached garage.
Low battery
A single short chirp at regular intervals.
End of life
CO sensors wear out, usually after 5 to 10 years; many alarms signal this with a different chirp pattern.
Malfunction
Error codes or random beeping can mean a faulty unit.
How to fix it, step by step
- 1
If the alarm is sounding loudly: get everyone and pets outside to fresh air, then call 911 or your fire department from outside.
- 2
Do not go back in until responders say it is safe, even if the alarm stops.
- 3
If it is only chirping: check the manual or label to match the chirp pattern.
- 4
Replace the battery if it is a low-battery chirp, then press the test button.
- 5
If it signals end of life, replace the whole alarm.
- 6
Have a technician inspect fuel-burning appliances once a year.
Tools and materials
- Replacement battery
- Step stool
- New CO alarm if expired
Approximate DIY cost: $5–$60
Call a pro when
- The alarm went off and you have fuel-burning appliances
- You need hardwired or interconnected CO alarms
- Appliances need inspection
Carbon Monoxide Detector Beeping cost
| Job | Typical cost |
|---|---|
| Battery-powered CO alarm | $20–$60 |
| Combination smoke and CO alarm | $30–$70 |
| Electrician to install hardwired CO alarm | $100–$250 |
| Furnace or gas appliance inspection | $80–$200 |
Ranges are typical US prices compiled by FixHomeCost. Prices vary by region, home and contractor, so compare 2–3 local quotes.
Common questions
What does 4 beeps on a carbon monoxide detector mean?
On many models, a repeating pattern of 4 loud beeps and a pause signals dangerous carbon monoxide. Get outside and call 911.
Why is my carbon monoxide detector chirping every minute?
Usually a low battery. Replace it and test the alarm. If it still chirps, the alarm may be at end of life.
Where should carbon monoxide detectors be installed?
On every level of the home and outside each sleeping area, following the manufacturer instructions and local code.
How long do carbon monoxide detectors last?
Typically 5 to 10 years, depending on the model. The expiration or manufacture date is printed on the back.
Related guides
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