A mist-generating device comprising: a housing defining a misting chamber (150, 160); at least one ultrasonic transducer electrically connected to a power supply; a memory device storing a plurality instructions which, when executed by a processor, cause the processor to operate with the power supply to constantly monitor and self-adjust at least one of a voltage and a current to the ultrasonic transducer; an inlet to the misting chamber; a first space having a first volume fluidly connected to the inlet, the first space having a first boundary adjacent to the inlet and a second boundary at a beginning of a channel located above the at least one ultrasonic transducer; a second space having a second volume fluidly connected to the first space the second volume being smaller than the first volume, the second space having a first boundary that borders the second boundary of the first space and a second boundary located where the channel begins to narrow; characterised in that the device comprises a third space having a third volume fluidly connected to the second space, the third volume being larger than the second volume and having a first boundary that borders the second boundary of the second space and a second boundary at an end of the channel; and an outlet from the misting chamber in fluid connection with the third space, the channel ending at the outlet, wherein the at least one ultrasonic transducer is included in the first space, wherein the second space is positioned such that mist generated by the at least one ultrasonic transducer flows vertically from the first space to the third space while accelerating through the second space to enable further mist to be created by the at least one ultrasonic transducer in the first space, and wherein the third space is configured to be larger than the second space to prevent the mist from exiting the outlet in an uncontrolled manner. a housing defining a misting chamber (150, 160); at least one ultrasonic transducer electrically connected to a power supply; a memory device storing a plurality instructions which, when executed by a processor, cause the processor to operate with the power supply to constantly monitor and self-adjust at least one of a voltage and a current to the ultrasonic transducer; an inlet to the misting chamber; a first space having a first volume fluidly connected to the inlet, the first space having a first boundary adjacent to the inlet and a second boundary at a beginning of a channel located above the at least one ultrasonic transducer; a second space having a second volume fluidly connected to the first space the second volume being smaller than the first volume, the second space having a first boundary that borders the second boundary of the first space and a second boundary located where the channel begins to narrow; characterised in that the device comprises a third space having a third volume fluidly connected to the second space, the third volume being larger than the second volume and having a first boundary that borders the second boundary of the second space and a second boundary at an end of the channel; and an outlet from the misting chamber in fluid connection with the third space, the channel ending at the outlet, wherein the at least one ultrasonic transducer is included in the first space, wherein the second space is positioned such that mist generated by the at least one ultrasonic transducer flows vertically from the first space to the third space while accelerating through the second space to enable further mist to be created by the at least one ultrasonic transducer in the first space, and wherein the third space is configured to be larger than the second space to prevent the mist from exiting the outlet in an uncontrolled manner.