What is the significance of UPS output Power Factor?
With the loads presented to a domestic UPS being resistive (incandescent lamps) / inductive (ceiling fans) / capacitive (CFL / LED lamps), the probability of the reactances cancelling out does exist.
The UPS manufacturer may hence assume a power factor of 0.9 (midway between 0.8 &amp; 1!) and give the rating in kW in addition to kVA.
The kW rating would be of help in selecting the UPS since the loads would be rated only in watts.