Which of the following is a common symptom of a malfunctioning air conditioner?

A common symptom of a malfunctioning air conditioner is the presence of unusual noises and water leaks. When an air conditioning system is operating properly, it typically runs quietly and effectively removes humidity from the air without creating excess water. If you start noticing strange sounds like grinding, squealing, or hissing, it may indicate that there are mechanical issues, such as worn-out parts or a failing compressor. Additionally, water leaks can be indicative of multiple problems, such as a clogged drain line or a malfunctioning condensate pump, which can lead to further complications if not addressed promptly. These signs signal that the system needs attention to restore proper function and prevent further damage.

In contrast, consistently low energy bills and improved indoor air quality would generally indicate that the air conditioning system is operating well, rather than malfunctioning. Excessive cooling can sometimes be a symptom but may also occur in situations where thermostat settings are incorrect or other factors are influencing comfort, making it less definitive as a sign of malfunction compared to unusual noises and water leaks.