If you can't see it, smell it or taste it, how do you know if carbon monoxide is trapped in your home? Carbon monoxide is the result of incomplete combustion of liquid, gaseous or solid fuel. Before you light the first fire of the heating season, the Chimney Safety Institute of America (CSIA) recommends you take the following safety measures to keep your home free of carbon monoxide.

Take a moment to look around your home for the following warning signs that may point to potential problems with carbon monoxide levels:

Moisture on inside of windows
High humidity smell within the home
Black streaks on walls and around registers and baseboard radiators
The CSIA also advises you to have your heating system serviced annually and be certain that the technician inspect furnaces for missing furnace panels and ductwork, or open cold air returns. If these situations exist in your home, they should be repaired.

The National Fire Protection Association (NFPA) recommends that all chimneys be inspected on an annual basis by a qualified professional to prevent chimney fires and carbon monoxide hazards. The CSIA adds that the best choice is a professional certified by the Chimney Safety Institute of America.

According to a report published by the Consumer Product Safety Commission, carbon monoxide poisoning deaths associated with heating systems jumped almost 60 percent from 1999 to 2000.

Carbon monoxide poisoning symptoms frequently mimic common wintertime illnesses such as influenza, headaches and seasonal affective disorder. Due to the regularity of the symptoms, carbon monoxide poisoning can easily be misdiagnosed.

"Chimneys, including flue pipes for freestanding stoves, transport hot toxic gases and carbon monoxide from the heating system to the outdoors," notes Ashley Eldridge, CSIA director of education. "It's vital that they operate properly to reduce the risk of carbon monoxide coming back into the home. A professional can diagnose and solve many problems."

The increase in carbon monoxide poisonings may be directly linked to the fact that today's houses are more airtight due to energy conserving measures. Consequently there is less fresh air coming into a home and not as many pathways for stale or polluted air to leave it. When furnaces and boilers are starved of the oxygen needed to burn fuels completely, carbon monoxide is produced. Many newer houses are so airtight that powered exhaust fans in the kitchen and bathroom can overcome the draft in the furnace chimney and literally pull the toxic gases into the living space.

The new high-efficiency gas and oil furnaces, when hooked up to existing flues, often do not perform at an optimum level. The differences in performance create conditions that allow combustion byproducts to more easily enter home living spaces.

Tight construction and performance conditions join a number of older, ongoing problems including damaged or deteriorating flue liners, soot build-up, debris clogging the passageway, and animal or bird nests obstructing chimney flues that may lead to carbon monoxide becoming trapped in a home.