What is a potential issue if an appliance is not properly vented?

When an appliance is not properly vented, one significant concern is the potential for air quality issues. Proper venting is crucial for the safe operation of gas appliances, as it ensures that combustion gases, including carbon monoxide and other harmful pollutants, are effectively expelled from the living space. If these gases are allowed to accumulate indoors due to inadequate or faulty venting, they can pose serious health risks to occupants. Poor indoor air quality can lead to symptoms such as headaches, dizziness, and respiratory problems, along with more severe long-term health consequences.

In contrast, options like increased energy efficiency, reduced operational noise, and lower maintenance costs do not typically relate to the consequences of improper venting. Lack of proper venting would likely do the opposite of improving energy efficiency, increase noise due to pressure imbalances, and potentially raise maintenance costs due to damage or increased wear on the appliance. Thus, the link between improper venting and air quality issues is clear and critical for ensuring safety and well-being in environments where gas appliances are used.