Can a carbon monoxide detector cause a false alarm?

Author: Dr. Jamarcus Marvin III  |  Last update: Friday, November 14, 2025

Carbon monoxide detectors are crucial for home safety, but sometimes they can trigger false alarms. Understanding why these occur and what different alarm sounds mean is essential for your safety. Let's explore common causes of false alarms and how to interpret your detector's beeps.

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.

Why does my carbon monoxide alarm go off for no reason?

The carbon monoxide alarm going off could mean the gas is present in your home or office, or simply indicating the battery or alarm needs replacing.

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 you know if your carbon monoxide detector is faulty?

Carbon Monoxide Detector Maintenance

To check your device, make sure the battery is in good condition then press and hold the “test” button until you hear a loud beep. If you don't hear a sound, the unit needs to be replaced.

Carbon Monoxide Detectors-When Zero Doesn't Mean Zero

What can trigger a carbon monoxide alarm?

CO alarms are designed to warn you of any unusual build-up of CO in your home. These higher levels of CO may occur from improperly maintained, installed or used fuel-burning appliances, backdrafting appliances or fireplaces, or idling cars in garages.

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.

How to tell if carbon monoxide is leaking?

What Are Signs of Carbon Monoxide in Your Home?
  1. Yellow or orange flames coming out of your gas appliances instead of the usual blue flame.
  2. Dark and sooty staining on or around gas appliances.
  3. Pilot lights that frequently blow out.
  4. Increased condensation on windows.
  5. Solid fuel fires burn much slower than usual.

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.

Why do carbon monoxide alarms go off at night?

Your carbon monoxide alarm is going off for one of the following reasons: It is doing its job properly and detects CO pollution in the air. It is a false alarm caused by other household items. The detector is malfunctioning or the batteries need changing.

Does the fire department charge to check for carbon monoxide?

In most areas, the fire department does not charge to respond to carbon monoxide alarms or to check for the presence of CO in a residence. However, policies can vary depending on the jurisdiction or specific fire department. It's always a good idea to contact your local fire department for specifics on their policies.

What appliances cause carbon monoxide?

The most common causes of carbon monoxide building up are incorrectly installed or poorly maintained or ventilated appliances – like stoves and hot water heaters. Poorly ventilated fireplaces and other gas- or wood-burning appliances can also pose danger.

Why is my carbon monoxide alarm 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.

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.

How to tell if a carbon monoxide alarm is false?

4 beeps and a pause: This means that there is carbon monoxide in the air and you should seek fresh air immediately and call 911. 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.

Can a carbon monoxide alarm go off by mistake?

Smoke and carbon monoxide (CO) detectors can false alarm for several reasons. False or nuisance alarms are when your smoke detector or CO alarm goes off, but there is no presence of smoke or carbon monoxide in your home.

Can a power outage cause a carbon monoxide detector to go off?

Although a power outage might cause a false alarm for hardwired carbon monoxide detectors, they typically have a battery backup that should prevent that from occurring. When you hear your carbon monoxide detector go off during a power outage, investigate it.

How long can you live in a house with a carbon monoxide leak?

Severe leaks can cause this problem in just five minutes. The EPA states that exposure to concentrations of nine ppm or more for eight hours is enough to produce harmful health effects for at-risk individuals. Exit the property and call 911 if you suspect your home has a gas leak.

How do I use my iPhone to detect carbon monoxide?

Go to the Home app on your iPhone or iPad. , then tap Home Settings. Tap Safety & Security. Tap Sound Recognition, then turn on Smoke & CO Alarm.

What part of the car does carbon monoxide leak from?

Risks Specific to Defective Exhaust Systems

Even a properly tuned gasoline engine will produce more than 30,000 parts per million (ppm) of carbon monoxide in the exhaust stream before the catalytic converter. Engines that are poorly maintained or defective can result in exhaust leaks.

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.

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.

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.

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