What does a carbon monoxide detector do and how does it work?

Difficult to detect and treat once the damage is done, carbon monoxide is known as the silent killer. This sneaky, toxic gas finds its way into your home through a wide range of seemingly harmless sources.

Even in small doses carbon monoxide can be harmful and may even cause permanent damage if not caught quickly, and heavy exposure can be lethal in the worst cases.

According to the Journal of the American Medical Association, carbon monoxide poisoning is the leading cause of accidental poisoning deaths in the U.S. The Center for Disease Control reports carbon monoxide poisoning sends about 15,000 people to the emergency room and kills 480 people each year. This is a type of gas exposure that should not be taken lightly.

What is carbon monoxide?

Carbon monoxide is an odorless, colorless, and tasteless gas that is near impossible to identify without a proper detector. It is caused by fuels not burning completely, including wood, gasoline, coal, propane, natural gas, gasoline, and heating oil. This unburned fuel can come from anything from clothes dryers, water heaters, and ovens to ranges, a fire-burning fireplace, or a car left running in a closed garage.

When carbon monoxide passes through the lungs, it enters the red blood cells and binds to hemoglobin in the same place as oxygen. This forms carboxyhemoglobin, which interferes with the transportation and gas exchange of oxygen in the red blood cells. This starves the body of oxygen, permanently damages brain and lung tissue, and induces suffocation. Perhaps most troubling is that before symptoms turn lethal, they may come off as symptoms of a flu or cold, such as shortness of breath, nausea, or mild headaches.

One way to prevent extreme or even mild exposure to carbon monoxide is to install a carbon monoxide detector or detectors in your home, either on their own or connected to a full security system.

How do carbon monoxide detectors work?

Carbon monoxide detectors sound an alarm when they sense a certain amount of carbon monoxide in the air over time. Different types of alarms are triggered by different types of sensors.

  • Biomimetic sensor: A gel changes color when it absorbs carbon monoxide, and this color change triggers the alarm.
  • Metal oxide semiconductor: When the silica chip's circuitry detects carbon monoxide, it lowers the electrical resistance, and this change triggers the alarm.
  • Electrochemical sensor: Electrodes immersed in a chemical solution sense changes in electrical currents when they come into contact with carbon dioxide, and this change triggers the alarm.

Once the alarm sounds, the carbon monoxide detector must be in a carbon monoxide-free environment to reset itself.

What do I do if my carbon monoxide detector goes off?

First, don't panic. Gather everyone in your house and move outside for fresh air. Survey their health, checking for any flu-like symptoms that could suggest poisoning. If these symptoms are apparent, call 911 immediately.

If you can, open all doors and windows to air out your home before heading outside. If possible, do not reenter your home until the alarm stops sounding or it has been approved safe by the authorities. Contact a professional to evaluate all of your fuel-burning appliances and any other possible sources of carbon monoxide to prevent a future occurrence.

Where should I place a carbon monoxide detector?

First find out if your local laws require you to have a particular type or configuration of carbon monoxide detectors. Make sure you do all of your research before making this investment.

According to the National Fire Protection Agency (NFPA), carbon monoxide detectors should be installed in a few different locations:

  • Outside the doors of sleeping areas
  • On each floor of your home
  • Anywhere else required by local laws

Next, decide if you want to go with a detector that is battery-operated or plug-in, which will need to be placed near a wall outlet. Plug-ins are usually movable from room to room when necessary, but if there is a power outage, you will need some sort of battery backup for them to continue working. A battery-operated unit is usually permanently installed somewhere in your home, often at the same time as a smoke detector or other security system. You can also decide whether or not to link one to the rest of the detectors installed throughout your home in case one goes off in another part of your home.

For more information about carbon monoxide detectors for your home, be sure to check out our CO Monoxide Detector Buyer's Guide.

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