Carbon Monoxide (CO) is an odorless, invisible gas produced whenever any fossil fuel such as oil, gas, kerosene, wood, or charcoal is burned. Hundreds of people die each year from CO poisoning caused by malfunctioning, misadjusted or improperly used fossil fueled appliances. If these appliances are maintained and used properly, the amount of CO produced is not hazardous. However, if these same appliances are not working properly or are installed and/or adjusted incorrectly, dangerous levels of CO can result that may not be known by simply sampling the indoor air of the building.

A good Carbon Monoxide analysis is performed by measuring CO in the undiluted flue gasses of the appliance being tested, i.e. "furnace, water heater, boiler etc". Also a draft measurement in the flue pipe should be performed where applicable. Furthermore a comparative sampling of both the indoor air and the outdoor air of the home or building environment for CO should be performed.

It is vitally important to understand the difference between actual CO flue gas measurement as opposed to a stroll through the house measuring for CO in the ambient air or at the registers.  Measuring for CO only in the indoor air is an inaccurate and dangerously short sighted approach to CO analysis.