Home Inspection Articles

Carbon Monoxide – Know the Symptoms and Sources

Posted by Olivia Hunt on Nov 5, 2012 4:08:00 PM

carbonmonoxidedectectorCarbon Monoxide (CO) is known as the “Great Imitator” as symptoms of CO poisoning are very similar to the flu. It is a colorless, odorless, tasteless gas making it impossible for a homeowner to detect. CO is a by-product of incomplete combustion such as unburned fuel like gas, oil, wood, etc. Low concentrations of CO can go undetected and can contribute to ongoing, unidentified illnesses. At high concentrations, it can be deadly. Without knowing the symptoms and areas of the house that may be the cause, it poses a dangerous threat to homeowners.

 Why Is It Dangerous?

Air with CO can be very dangerous as it deprives your body of oxygen. When you take a breath of air with CO in it, the oxygen within your bloodstream is displaced with Carbon Monoxide. Depending on the amount of CO in the air, it can result in suffocation.


What Are The Symptoms?

Continued exposure or high concentrations can cause the following symptoms:

  • Confusion
  • Cardiac problems
  • Severe headaches
  • Brain damage
  • Breathing difficulties
  • Dizziness
  • Death

Long term exposure to low concentrations can cause the following symptoms:

  • Slight headaches
  • Fatigue
  • Shortness of breath with only moderate exertion
  • Nausea
  • Dizziness
  • Confusion

Who Is At Greater Risk?

  • Senior Citizens
  • Pregnant women and their unborn babies
  • Young Children
  • Individuals with respiratory or coronary problems

Note: Vulnerable people who are exposed even to low levels of CO for long time periods may have similar health affects as those exposed to high concentrations of CO.

What Can Produce CO in Our Homes?

Anything that burns fuel or generates combustion gases can be a source of Carbon Monoxide. This includes: 

1.      Automobile exhaust in attached garages & non-vented fuel burning appliances

Automobile exhaust in attached garages is responsible for 60% of all CO alarms. People who warm up their cars in the garage are trapping CO inside.  When CO collects inside the garage, it can find its way into the home instead of going outside.

Non-vented fuel burning appliances include barbecues or gasoline powered equipment operating in an attached garage, basement, or enclosed area. It’s important to ensure CO isn’t trapped inside an enclosed area.

2.      Gas cooking appliances

Reported to account for 20% of CO alarms, this type of CO may be a result of misused, poorly maintained, poorly installed or unvented cooking appliances such as gas stoves and ovens. When having your furnace or boiler inspected annually, get any gas cooking appliances inspected as well. Often times gas stoves and ovens aren’t properly vented.

3.      Fireplaces and heating stoves

This is one of the most common and serious causes for CO build up and has been reported to account for up to 20% of CO alarms. When fireplaces and wood stoves do not have the proper venting, the CO remains inside the house instead of being safely expelled outside. Venting problems can include blocked chimney flues, inadequate venting as a result of poor installation or poor maintenance.

A leak in a chimney or flue pipe can also cause issues with CO coming back into your home.

4.      Poor combustion at furnace

Inadequate air to your furnace can lead to incomplete combustion which can result in poor efficiency as well as the production of CO gases. If your furnace has a cracked heat exchanger, it is possible to get CO into the circulating air. It is imperative that we do not deprive our heating equipment and fuel burning appliances of air; especially in air-tight homes where running exhaust fans can result in a shortage of combustion air. Combustion air is essential for safe operation of furnaces, water heaters, and other fuel burning equipment.

How Can I Guard Against Carbon Monoxide Poisoning?

The first line of defense is to have your home heating systems, fuel burning appliances, flues and chimneys checked and/or cleaned annually by a specialist. Specialists should check for:

  • Blocked openings to flues and chimneys
  • Cracked, rusted, or disconnected flue pipes
  • Dirty filters
  • Rusted or cracked heat exchangers
  • Soot or creosote build-up inside fireplaces and chimney flues
  • Exhaust or gas odors
  • Attached garages require gas proofing and automatic closers for doors into the home
  • Adequate combustion air
  • Adequate venting on indoor combustion appliances (i.e-gas stoves)

The second line of defense is a Carbon Monoxide detector.

Carbon Monoxide Detectors

How Do They Work?

Carbon Monoxide detectors sample the air at specific time intervals. A microchip inside the detector stores the reading and keeps track of the level of CO that the detector is exposed to over time.

Where to Install a Carbon Monoxide detector?

You should usually have one or more Carbon Monoxide detectors in your house but follow the manufacturer’s recommendations. This usually means one per floor. Be sure to maintain and test the detector regularly as instructed by the manufacturer.

If you want to learn more about your home and enjoyed these tips, order a copy of the Home Reference Book. You can also visit the Canadian Mortgage and Housing Corporation as they are an excellent and credible source for information on Carbon Monoxide.

Topics: Home Reference Book, Home Inspection, Homeowner Tips