Mitsubishi mini-splits are not noisy at all, operating at about 19 to 40 decibels (dB) depending on the model and mode. For comparison, a normal conversation is about 60 dB, a whisper is about 30 dB and a quiet library is around 40 dB.
So, Mitsubishi mini splits generally operate quieter than a normal conversation, often closer to whisper or quiet room noise levels. This makes them good for residential and commercial use where low noise is preferred as the operate much quieter than window AC units or older HVAC systems—providing comfort without noise disturbance.