Abstract: Most people would agree that air conditioners should be as quiet as possible. However, it can be shown that air-conditioner noise can have a positive effect in that it can mask other, more unwanted, noises. It is, therefore, desirable that the noise produced by air conditioners should be as acceptable as possible. A series of experiments was conducted using simulated air-conditioner noise to investigate the loudness and sound qualitites of air-conditioner noise and to examine the appropriateness of applying ISO 532B to air-conditioner noise.