Which of the following should be checked if an A/C unit is blowing warm air?

The correct choice focuses on air filters and refrigerant levels when diagnosing an A/C unit that is blowing warm air because these two components are directly linked to the cooling performance of the system.

Air filters can accumulate dust and debris over time, which restricts airflow. This restriction can cause the evaporator coil to freeze, resulting in inadequate cooling and warmer air being pushed through the ducts. Keeping air filters clean is essential for optimal airflow and efficiency.

Refrigerant levels are also critical for proper operation. If the refrigerant is low due to leaks or other issues, it can prevent the system from absorbing heat effectively, causing the air being blown into the living space to feel warm. Adequate refrigerant is essential to facilitate the heat exchange process that provides cooling in an A/C system.

Checking these two aspects can help identify common issues that lead to warm air blowing from an A/C unit and guide necessary repairs or maintenance to restore proper cooling functionality.