Carbon Monoxide Detector Beeping: Chirp or Real Alarm

Detectors beep for more than one reason, and the pattern matters more than the urge to make the noise stop. Read the label on the unit you own if you can do that without delaying a real alarm. The patterns below are the common ones. Your model’s printed instructions win if they differ.

If it is a full alarm

A rapid repeating horn, or whatever pattern the manufacturer calls the carbon monoxide alarm, means leave. Get people and pets out. Call emergency services from outside. Do not look for the furnace, do not restart anything, and do not go back in because the horn stopped. Stopping can mean the air shifted, not that the source is gone. Firefighters and the gas utility are the people who clear a house.

Headache, nausea, dizziness, or confusion in the house make this an alarm even if you are unsure about the beep pattern. Get out.

If it is a chirp

A single chirp about once a minute, with no alarm pattern and nobody feeling sick, is often a low battery or a detector that has reached its end of life. Many sensors expire around the date printed inside the cover, often well before ten years. Replace the battery with the type the label asks for, or replace the detector if it is expired or it keeps chirping on a fresh battery.

• Do not take the battery out and leave the detector silent overnight. A quiet detector is not a safe house.
• Do not move it into a drawer to stop the noise.
• If a chirp starts and someone feels ill, treat it as an alarm and leave.

After the house is cleared

A furnace, water heater, fireplace, or attached garage can be the source. That inspection happens after the emergency response, not instead of it. We do not ask anyone to run a furnace as a test while an alarm is unexplained. When the house is safe and heat will not run, heating repair can check the furnace itself. The detector and the emergency call come first.

Common questions