The noise level of a cooler can vary depending on the type of cooling unit and the specific model. Some cooling units are designed to be very quiet, while others may produce more noise – however, the noise is always no more than the sound of a refrigerator running. Ducted systems tend to be less noisy than ductless systems. It's best to check the decibel level of the unit before purchasing, or consult with a professional to determine the noise level of a specific model.