Testing Carbon Monoxide Alarms

Test Your Carbon Monoxide Alarm(s) (General Recommendations)

Carbon monoxide is a colorless, odorless, poisonous gas; it can be generated in your house when fuel- burning appliances like furnaces and water heaters malfunction, or when generators and other devices are used improperly in or near the home. Carbon monoxide alarms can be used to warn you in the event that elevated and dangerous levels of the gas develop in your home. 

Carbon Monoxide alarms come in two main designs. The first is a wall or ceiling mounted alarm. This can be a standalone C02 alarm or it can be a combination C02 and smoke alarm. There is normally a button on the outside of the alarm that you will push to test. Please refer to manufacturer instructions for proper testing.

The second common type of Carbon Monoxide alarm is pictured below. This is a plug-in alarm and it can normally be tested by pushing a 'Test' button on the front of the device.  Please refer to manufacturer instructions for proper testing. 

What Needs To Be Done:


You need to regularly test your carbon monoxide alarm to ensure that it's working. Testing is recommended on a monthly basis.     

Why Do It?

Consult the manufacturer's instructions to see how often the alarms need to be tested, but, as a rule of thumb, it's a good idea to test your alarm once a month, whether it's battery-powered or hardwired.  

You should change the batteries at least every six months (applies to battery operating alarms). (Even hardwired alarms usually have backup batteries). The CPSC urges people to make it a habit to change the batteries in their carbon monoxide detectors in the spring and fall  when they change the clocks for Daylight Saving Time. 

How To Do It: 

The manufacturer's instructions or product literature will provide information on how to test your carbon monoxide detectors. Many can be tested using the following steps: 

Step 1. Find the test button. 

Step 2. Press and hold the button for a few seconds.

Step 3. Listen for the beeping that tells you the device is working.

Step 4. Release the button.

Step 5. Change the batteries or replace the alarm immediately if it fails the test. 

Prevent carbon monoxide from forming in your home 

It's also a good idea to take steps to prevent carbon monoxide in your home. Here are a few tips from the U.S. Consumer Product Safety Commission. 

  • Make certain that appliances are properly installed without any gas leaks.
  • Never self-service fuel-burning appliances without the proper knowledge and tools.
  • Install an alarm in the hallway outside the bedrooms in each area of the home.
  • Never use a generator or fuel-burning camping equipment in your home or in an enclosed space.
  • Never burn charcoal in an enclosed area, even with the windows open.
  • Never idle a car in a garage, even with the garage doors open.
  • Never heat your home with gas appliances such as your oven or clothes dryer.

Symptoms of carbon monoxide poisoning:

The Centers for Disease Control and Prevention says the following are symptoms of carbon monoxide poisoning:

  • Headache
  • Dizziness
  • Weakness
  • Nausea
  • Vomiting
  • Chest pain
  • Confusion

High levels of inhalation can cause loss of consciousness or even death, the CDC says.

Carbon monoxide poisoning is a serious concern. And prevention is key. Although carbon monoxide alarms can help to warn you of dangerous levels of the gas in your home, you should also take steps to avoid the production of carbon monoxide. Always test your carbon monoxide detector and regularly changing the batteries to help stay protected. If you notice any of the symptoms of carbon monoxide poisoning, even if your alarm does not sound, seek professional medical attention immediately.    

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