Why Your Carbon Monoxide Detector Is Beeping

How to check a CO detector and when to reset it

A woman pushes the test button to reset her beeping carbon monoxide detector.

​mikroman6 / Moment / Getty Images

Carbon monoxide (CO) is a colorless, odorless gas that can accumulate in closed spaces like a home or office. Prolonged exposure can result in permanent brain damage or even death. When functioning correctly, carbon monoxide detectors alert you to the presence of the toxic gas in time to take life-saving action. But what if your carbon monoxide detector beeps for no apparent reason?

While you should take any alarm seriously, carbon monoxide detectors often beep or chirp in non-emergency situations. Here are the most common reasons why a carbon monoxide detector beeps, and what to do when it happens.

Causes of Carbon Monoxide Detectors Beeping

When a carbon monoxide detector beeps or chirps at regular intervals, it is usually because of a problem with the battery or an internal malfunction.

  • Battery problems: Most carbon monoxide detectors are designed to warn residents of a decaying battery. Once the battery has dropped below a certain threshold, the device will beep or chirp every 30 to 60 seconds. If you have a plug-in carbon monoxide detector, the backup battery may be faulty or installed incorrectly.
  • Internal faults: When a carbon monoxide detector suffers from an internal defect, it will usually beep or chirp at regular intervals. Some units, including smart carbon monoxide detectors, can provide information about the issue.
  • End of life: Carbon monoxide detectors have a limited lifespan. When a unit reaches the end of its life, it will start beeping or chirping at regular intervals to let you know that it's time for a replacement. The frequency depends on the specific model, but it will typically beep more often than a detector that has a weak battery.

Sources of Carbon Monoxide

Carbon monoxide is usually produced in the home by fuel-burning devices, like furnaces, stoves, gas clothes dryers, and fireplaces. Under normal circumstances, these devices release very little carbon monoxide, but that can change if they malfunction.

Some sources of carbon monoxide can be avoided through best practices. For example, you should never operate an outdoor grill or propane heater indoors. Generators should be operated a safe distance away from the home, as they create a lot of carbon monoxide during regular operation. Never run a generator inside your garage, even if the garage door is open.

Cars can also be a source of carbon monoxide in the home. Never leave a car running in your garage, especially with the garage door closed. Like generators, even running a car near a window or door of your home can cause exhaust fumes to accumulate inside.

Is It Safe to Reset a Carbon Monoxide Detector?

Most carbon monoxide detectors are designed to be reset after an alarm (real or false), or after replacing the battery. Resetting a carbon monoxide detector is perfectly safe, as long as the device hasn't reached the end of its operational life.

After a carbon monoxide detector sounds the alarm, it's critical that you identify and remove the source of carbon monoxide and ventilate the affected area. Emergency responders can check the source of carbon monoxide and remedy the situation.

How to Fix a Beeping Carbon Monoxide Detector

If you've determined that there is not a dangerous buildup of carbon monoxide present, you will have to figure out what caused the alarm.

If your carbon monoxide detector sounds an alarm, don't take any chances. Press the test or reset button and then relocate everyone, including pets, to fresh air. Call emergency services, and wait for them to provide the all-clear before reentering the structure.

Here are the steps to take if your carbon monoxide detector is beeping:

  1. Check the Battery

    The most common cause of a beeping carbon monoxide detector is a dying or defective battery. If the device is beeping or chirping at regular intervals, typically between about 30 and 60 seconds, then it's probably because of the battery.

    Some carbon monoxide detectors come with a built-in sealed battery that's designed to last the life of the device. If you have one of these units, then you will have to replace the entire device.

    Some plug-in or hardwired units have backup batteries. If you have one of these units, try replacing the battery. You may also have to reset the device for it to stop beeping.

    Some carbon monoxide detectors include a battery light that will turn yellow or red when the battery is weak. Consult your owner's manual or contact the manufacturer for more information.

  2. Check for Errors

    When a carbon monoxide detector malfunctions, it may provide an error indication or message. Some units have an LED that lights up if an error is detected, and others have a display that will show a message like ERR or ERROR. Some units will perform a double chirp every 30 seconds instead of a single chirp.

    You can usually retrieve error codes by pressing the test or peak level button, but you can't do much with one of these codes on your own. Carbon monoxide detector manufacturers require you to contact them with your error code to receive more information.

    Smart carbon monoxide detectors typically include a connected app that you can install on your smartphone. These apps sometimes allow you to view error messages, which can help narrow down the problem.

    If you are sure that there's isn't a dangerous buildup of carbon monoxide present, try cleaning the inside of the detector with canned air or a vacuum. Then reset the unit.

    If the error comes back, verify that there is not any carbon monoxide in your home, and then contact the manufacturer of the device for additional assistance. In most cases, you will have to replace the detector.

    Carbon monoxide detectors in this state are not capable of alerting you to the presence of carbon monoxide. Exercise extreme caution, as you will have no way to tell if carbon monoxide is present in your home until you fix the problem.

  3. Check the Age of Your Detector

    Carbon monoxide detectors are designed with a built-in shelf life because their internal sensors degrade over time. After a while, the sensor is no longer able to detect the presence of carbon monoxide adequately.

    If your carbon monoxide detector is beeping or chirping at regular intervals, even with a fresh battery, it may have ceased functioning. Some carbon monoxide detectors are designed to last up to 10 years. Check your owner's manual or contact the manufacturer if you think yours has failed early.

    If your carbon monoxide detector is beeping due to having reached the end of its operational life, the only fix is to replace it with a new unit.

    A carbon monoxide detector that has reached the end of its life will not sound an alarm if carbon monoxide builds up inside your home.

  4. Eliminate Sources of False Alarms

    If your battery is fine, your detector doesn't indicate an error, and it's relatively new, then it might be due to a false alarm. In some cases, proximity to a gas-burning furnace or stove can cause issues.

    Try moving your carbon monoxide detector at least 15 feet away from these appliances, and see if that fixes the problem.

    If your gas-burning appliance isn't burning its fuel completely, it will create excessive amounts of carbon monoxide. If the pilot light has a yellow or orange flame, that's an indicator of incomplete combustion. To avoid carbon monoxide poisoning, you should have the appliance repaired or replaced as needed.

  5. Reset Your Carbon Monoxide Detector

    Once you've ruled out a dangerous buildup of carbon monoxide, and gone through this list, you might have to reset the device.

How to Reset a Carbon Monoxide Detector

To reset a carbon monoxide detector, you must first connect it to a power source or install a fresh battery. In most cases, the reset process is automatic, so the goal is to silence the alarm while the detector resets itself.

If the detector was exposed to carbon monoxide, then move it to an area with fresh air before resetting it.

  1. Locate the Reset Button

    Look for a button labeled, reset, test, test/silence, or some other iteration. Consult your owner's manual or contact the manufacturer if you are unable to locate the reset button.

  2. Push and Hold the Reset Button for at Least 10 Seconds

    Carbon monoxide detectors that are hardwired or plug-in units must have power for the reset process to work. Make sure your device is plugged in and that power is available.

  3. Release the Reset Button

    If your device has successfully reset, it will typically beep or briefly illuminate an LED to show that it is working.

    Consult your owner's manual or contact the manufacturer for device-specific information.

Smart Carbon Monoxide Detectors Beeping

Smart carbon monoxide detectors are designed to provide more information than conventional units. They can link to your smart home system through a smart home hub. Usually, they allow you to control the detector through an app on your smartphone.

Smart carbon monoxide detector apps usually provide basic controls, like the ability to silence the alarm, which is useful during the reset procedure. Some of these apps are also designed to offer useful diagnostic information as well, which can help in troubleshooting a false alarm.

Since smart carbon monoxide detectors are designed to provide additional information through the connected app, you should make sure to check your app in addition to the steps outlined above. The problem may be still be due to the battery, but the app can help pinpoint the complication if you are experiencing another type of failure.