The Air Pro purifier operates at a noise level of 30-65 decibels, depending on the fan speed setting. At its lowest speed setting, the noise level is comparable to a whisper, and at its highest setting, it is similar to the sound of normal conversation. Molekule has manufactured this product with a quiet mode, in addition to its standard mode for the Auto Protect function, sleep mode, or quiet mode, that runs at a low noise level to avoid disturbing sleep, making it suitable for use in bedrooms and other quiet spaces up to 1000 square feet.