Can carbon monoxide detectors go off falsely?

Author: Ms. Lexi Johnson Sr.  |  Last update: Wednesday, September 3, 2025

While CO detectors are designed to be reliable, various factors can cause them to beep erroneously. False alarms can be caused by incorrect installation, placement near a source of fumes or steam, or even a buildup of dust and dirt on the sensor.

What can falsely set off a carbon monoxide detector?

Common causes of false alarms of carbon monoxide:
  • Close to cooking sources (10 feet minimum)
  • Close to sources of humidity (10-20 feet)
  • Near fireplaces.
  • Near water heaters.
  • Near furnaces.
  • Located in a poorly ventilated location like a garage, kitchen, or closet.

Can a carbon monoxide detector go off for no reason?

While false alarms can and do happen, you should always assume your detector is working properly. Once everyone is safely outside, dial 911 and let the dispatcher know your CO alarm has been triggered.

Can other things set off a carbon monoxide detector?

Exposure to the vapors from various household substances (such as paints and paint thinners, adhesives, hair spray, strong perfumes, plug-in and aerosol air fresheners, and household cleaning solvents with strong odors (like pine)) may cause your CO alarm to render a false alarm.

How do I know if my carbon monoxide detector is accurate?

If you're wondering how you can check that your carbon monoxide detector works, the answer is simple: testing. You should test your CO detector monthly to ensure your family's safety. The test button is the best way to test it because it will tell if the alarm is still sounding.

What Most Homeowners Don’t Know About Carbon Monoxide Detectors

How do I know if my carbon monoxide detector is malfunctioning?

1 beep every minute: This means that the alarm has low batteries and you should replace them. 3 beeps every minute: This means the alarm has encountered a malfunction and needs replacement. 5 beeps every minute: This means your alarm has reached the end of its life and needs to be replaced with a new alarm.

Does 3 beeps mean carbon monoxide?

Here's a simple guide: Smoke alarms alert you with three beeps in a row. Carbon monoxide alarms alert you with four beeps. A single chirp means the battery is low or the detector should be replaced.

What are two warning signs of carbon monoxide poisoning?

The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. CO symptoms are often described as “flu-like.” If you breathe in a lot of CO, it can make you pass out or kill you.

What to do if a carbon monoxide alarm goes off and then stops?

If you have a carbon monoxide detector chirping and then it stops, it's important to take the situation seriously, even if the alarm is no longer sounding. Even if the alarm has stopped, get everyone out of the home to a place with fresh air.

Will opening a window help with carbon monoxide?

If you experience symptoms that you think could be from CO poisoning: DO GET FRESH AIR IMMEDIATELY. Open doors and windows, turn off combustion appliances and leave the house.

Can cold cause carbon monoxide detector to go off?

Do Hot or Cold Temperatures Affect My Alarm? Our smoke, carbon monoxide, and combination alarms will perform between 40 and 100 degrees Fahrenheit. If the temperature drops, the battery may be impacted by the cooler temperature and chirp as it will read as, "Low."

What other gases can set off a carbon monoxide detector after?

Carbon monoxide alarms are vital pieces of safety equipment used to protect workers and residents from poisonous carbon monoxide gas. But, did you know that hydrogen gas from charging batteries can set off the alarms as well.

Should I call 911 if my carbon monoxide alarm goes off?

My carbon monoxide alarm is sounding. What should I do? Call 911 and report what is happening. Immediately leave your residence and wait for the fire department to arrive.

Why is my carbon monoxide detector going off for no reason?

While CO detectors are designed to be reliable, various factors can cause them to beep erroneously. False alarms can be caused by incorrect installation, placement near a source of fumes or steam, or even a buildup of dust and dirt on the sensor.

How to tell if smoke alarm doubles as a carbon monoxide detector?

Smoke alarms typically sound with 3 beeps in a row, while carbon monoxide detectors usually sound with 4 beeps. Press and hold the button on the front of the detector to test the alarm, and make note of how many beeps it produces. Press the button again, or press and hold it again, to turn off the alarm.

Can moisture set off a carbon monoxide detector?

Excessive moisture from a bathroom may set off your CO alarm.

Can anything else trigger a carbon monoxide detector?

Two Common Causes Of False Readings: You have a cigarette smoker in the home. Cigarettes give off carbon monoxide. Artificial components, such as lighted incense or air fresheners, can trick your detectors with low levels of CO emitted into the air.

What to do if your carbon monoxide alarm goes off in the middle of the night?

If the alarm on your carbon monoxide detector is going off in a continuous, shrill way, get outside to fresh air right away. Make sure you contact your emergency provider to give you the all-clear before re-entering your dwelling.

What does 4 beeps mean on carbon monoxide?

What Does an Emergency Alarm Chirp Mean? This meaning is probably the most self-explanatory. When your carbon monoxide detector chirps 4 times in a row and pauses, this means it has detected unsafe levels of carbon monoxide. This means your entire household should evacuate immediately and seek fresh air.

How to test a carbon monoxide alarm?

How to test your carbon monoxide detectors to ensure they are working properly? To test your carbon monoxide detectors, press and hold the test button on the alarm. The detector will sound 4 beeps, a pause, then 4 beeps for 5-6 seconds. Refer to the user manual for your specific model.

What are the symptoms of a gas leak?

Natural Gas Leak Physical Symptoms
  • Ringing in your ears.
  • A reduced appetite.
  • Pain in the chest.
  • Nosebleeds.
  • Blistering or pale skin.
  • Flu-like symptoms.
  • Dizziness.
  • Breathing difficulties.

How to clear carbon monoxide from a house?

If no one is feeling symptoms, ventilate the home with fresh air and turn off all potential sources of CO. That includes your oil or gas furnace, gas water heater, gas range and oven, gas dryer, gas or kerosene space heater, and any vehicle or small engine.

How to know if a carbon monoxide alarm is faulty?

Learn How Often to Replace CO Detectors
  1. End-of-Life warning will sound every 30 seconds.
  2. If the alarm has a digital display, it displays the ERR or END error code.
  3. The beep will ONLY STOP when the alarm is out of power.
  4. Replacing the battery WON'T STOP the beep.

How many times will a carbon monoxide detector go off?

If your detector is low on battery, you will likely hear a short chirp every minute. To warn of dangerous CO levels, most detectors will beep 4 or 5 times in a row about every 4 seconds.

Why is my Kidde smoke and carbon monoxide alarm going off randomly?

If your carbon monoxide alarm is chirping or beeping once every 60 seconds, it may signify: Low Battery – The carbon monoxide batteries need to be replaced. End of Life Warning – Seven years after initial power up, a Kidde CO alarm will begin chirping every 30 seconds.

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