Hi..

Inverters use variable fan speed to the external coolin coil on d outdoor unit..
On d normal aircon .. d external fan is either on or off [ meanin too tat de compressor cools de coolin fins for cold air only when de fan is on ] .. so it cant regulate temperature as well as de inverter units ..
I hv both types n its true tat d inverter regulates temperature better than de non inverter types .. cant really say much on its elec efficiency thou'[both makan lektrik]..

Cheers
D