Power factor below 1.0 means some current flows just to sustain a magnetic field (in motors, transformers) without doing useful work — utilities often bill industrial customers extra for this "reactive" demand.
Real power (kW, the useful part) and apparent power (kVA, what the wiring and generator actually have to supply) diverge as power factor drops — correcting it with capacitors reduces wasted current without changing the useful work being done at all.
Most domestic tariffs bill kWh only, so a poor power factor costs a householder nothing directly. And correcting displacement power factor does nothing for the harmonic distortion that dominates modern electronic loads — you can reach 0.99 displacement and still have a bad true power factor.
Estimate with the rule, then check it against the calculator that models it properly.
Open Power Factor Calculator →Power factor below 1.0 means some current flows just to sustain a magnetic field (in motors, transformers) without doing useful work — utilities often bill industrial customers extra for this "reactive" demand. Real power (kW, the useful part) and apparent power (kVA, what the wiring and generator actually have to supply) diverge as power factor drops — correcting it with capacitors reduces wasted current without changing the useful work being done at all.