Power factor is the ratio of the power your device uses compared to what it draws from the grid.  If there is zero lag between voltage and current, and your device does not waste any power, the power factor will be 1.   Otherwise if there is wastage, or the current and voltage are out of phase, you ended up pulling more power from the power socket than you are actually using.   For example, if your PF was 0.9, and you device used 1000W of power, then it would draw 1000/0.9=1111 W.  That means the grid actually needs to supply your device 1111W to operate - even though the device only uses 1000W.   A sparky should be able to measure the PF for your site (it is often done across larger circuits for the the site as a whole). Some nicer metered PDUs (like APC) can calculate the PF of the load you have plugged in.  An example is the APC 9953 (which is switched and metered - note this one has a 32A 240V input): https://www.apc.com/my/en/product/APDU9953/apc-rack-pdu-9000-switched-zerou-32a-230v-21-c13-3-c19/  ... View more