Carbon Monoxide: The Invisible Killer

What is Carbon Monoxide (CO)?

CO is an odorless, colorless gas (and is a biproduct of combustion). CO (CO) poisoning symptoms are similar to those of the flu, and include:

  • Dizziness
  • Fatigue
  • Headache
  • Nausea
  • Shortness of Breath

How CO Gets Into Your Home

Most homes use fuel to run certain appliances. Common fuels are wood, pellets, natural gas or propane (LP). The most common appliances using fuels are:

  • Fireplaces
  • Furnace or heating units
  • Ovens
  • Stoves
  • Water heaters


Generally these appliances are safe to use when installed and maintained correctly. Occasionally these appliances lack necessary routine maintenance and cleaning, installation or use of a given appliance was not in accordance with manufacturer's instructions, or they simply malfunction, causing the release of CO.

Running Vehicles

Additionally, some of our homes have attached garages or parking areas. The exhaust of a running vehicle in an area that is not properly ventilated is also a common source of CO in the home.

Is CO Present

The most reliable method to detect CO is through the use of CO Detectors. CO Detectors are inexpensive and readily available at most home improvement or department retailers. They are easy to use and provide reliable early detection and early warning of the presence of CO 24 hours a day, 7 days a week.

Which Type of CO Detector You Should Have

New Construction

If your home is new construction or you are currently building a home, detectors that are hard wired to the house electrical and have a battery back-up are required by law.

Built Prior to 2011

If your home was built prior to 2011 state law requires a CO Detector on each level of the home, and located near the sleeping areas. Purchased detectors may be battery operated, "plug-in" with battery back-up, or hardwired with battery back-up. Combination smoke / CO Detectors are also acceptable.

Installed detectors may have a digital readout, or may initiate a warning sound only, the choice is yours.

Where to Place CO Detectors

A CO detector should be placed on each level of the home near the sleeping areas. CO is slightly lighter than air, so it will move throughout the home with circulating air. The detector will function at both "outlet" level, or if you prefer, high on a wall or at ceiling level. The manufacturer's instructions for your unit will provide the most accurate placement recommendations for optimal effectiveness.

Image showing where to place CO alarms in your house

Responding to the Alarm

You should evacuate all residents (especially the very young and very old) to fresh air if possible.

If anyone is feeling nauseous, disoriented, has an unexplained headache, is unconscious or very tired, or has sudden onset of "feeling ill" in any way, call 911 immediately as medical assistance may be necessary.

If there are no signs of illness once everyone has been moved to a safe air environment, then call your natural gas provider.

Preventative Actions to Keep Your Home Safe

  • Make sure you follow manufacturers recommendations on the use and maintenance of fuel burning appliances.
  • Keep up on routine maintenance and cleaning of fuel burning appliances.
  • Test your CO Detector monthly.
  • Know and understand the different alerts on your particular model detector. A low battery alert is different than a full alarm. Keep and reference the instructions.
  • Replace the batteries in your detector at least twice each year (Remember: when you change your clock, change your batteries).
  • Replace alarms at manufacturer recommended intervals (Most CO detectors will work properly for approximately 5 years - know when yours will need replacement).

More Information

The following downloads contain more information: