What common issue can arise from improper furnace maintenance?

Improper furnace maintenance can lead to decreased efficiency and significantly increase the risk of carbon monoxide poisoning. When a furnace is not regularly serviced, various components may not function as they should. For instance, a dirty or blocked heat exchanger can lead to improper combustion, which not only reduces the furnace's efficiency but can also create dangerous conditions, allowing carbon monoxide, a colorless and odorless gas, to accumulate in the home.

In contrast, while increased heating bills, noisy operation, and frequent pilot light outages may also stem from maintenance issues, they do not carry the same level of risk to health and safety as the potential for carbon monoxide exposure. Decreased efficiency usually implicates higher bills, but the critical concern in maintaining safe operation is the prevention of carbon monoxide buildup. Therefore, emphasizing the importance of routine maintenance checks can help ensure efficient operation and protect against hazardous situations.