The device is super quiet. What can be a bit noisy is the inhalation and exhalation when breathing. This can be resolved by purchasing the hose connector adapter to use any hose, adding the QLite muffler and the Vcomm adapter. With this, the noise is similar to that of the Resmed Airsense 11. I use the generic HME for humidification, and it works very well for me.

I have the Transcend Micro CPAP Device, and the Resmed Airimini is much quieter than the Transcend Micro.

The option Resmed Aimini hard cover case is great, add additional protection.