Carbon monoxide is a by-product of combustion, which means it is emitted when any fuel is burned. Common sources of carbon monoxide in the home include:
- Blocked chimney opening
- Clogged chimney
- Portable heater
- Gas or wood burning fireplace
- Improperly installed gas kitchen range or carbon monoxide top vent
- Gas clothes dryer
- Operating barbecue grill in enclosed area such as a garage
- Corroded or disconnected water heater vent pipe
- Leaking chimney pipe or flue
- Cracked heat exchanger
- Automobile exhaust
All of these sources can contribute to a carbon monoxide problem in the home. If a home is vented properly and is free from appliance malfunctions, air pressure fluctuations or airway blockages, carbon monoxide will most likely be safely vented to the outside. But in today's energy efficient homes this is frequently not the case. Insulation meant to keep warm air in during winter months can trap carbon monoxide polluted air in a home year round. Furnace heat exchangers can crack, vents can become blocked, inadequate air supply for combustion appliances can cause conditions known as back drafting or reverse stacking, which force contaminated air back into the home.