Window air conditioner leak testing can be done using several methods. The soap bubble test is simple, where bubbles indicate leaks. Electronic detectors sense refrigerant in the air, while fluorescent dye highlights leaks under UV light. Ultrasonic detectors listen for escaping refrigerant sounds, and pressure decay tests monitor pressure loss in the system. For older systems, a halide torch can detect leaks by changing flame color. Each method varies in complexity, with some being quick and others requiring special tools or time.