What is a common symptom of low refrigerant charge in an air conditioning system?

A common symptom of low refrigerant charge in an air conditioning system is reduced cooling performance and ice formation. When refrigerant levels are low, the system cannot effectively absorb and release heat. This leads to insufficient cooling, as the air conditioning unit struggles to cool the air circulating through the ducts. In addition, low refrigerant can cause the evaporator coil to become too cold, resulting in condensation and ultimately ice formation on the coil. This ice buildup further restricts airflow and exacerbates cooling issues, creating a cycle of inefficiency in the cooling system.

The other choices do not accurately reflect the symptoms associated with low refrigerant charge. Increased energy efficiency is expected with optimal refrigerant levels, not when they are low. Improved airflow through ducting is typically due to a well-functioning system, not one with low refrigerant, which can lead to airflow restrictions. Constant humidity levels also depend on an adequately charged system; low refrigerant affects the system's ability to control humidity effectively.