kVA to kW Calculator

Power factor is one of the line items on a commercial electricity bill that most finance leads never look at, and that an audit will frequently find money sitting in. A site running at 0.85 power factor on a 400 kVA load is drawing 340 kW of real power and 211 kVAr of reactive power, and the supplier is charging for both. The reactive demand line on the bill, often quoted in kVArh, can be 1 to 3 percent of the total spend on a heavy industrial site, which on a £400,000 annual bill is real money for a one-off capacitor bank install.

The harder issue is capacity charges. DNO standing charges, transmission charges, and the new Targeted Charging Review banding all key off agreed capacity in kVA, not in kW. A site that has improved its power factor from 0.85 to 0.97 with a PFC retrofit can often negotiate a lower MIC band on the next contract anniversary, dropping fixed monthly costs without touching the kWh number. That kind of saving compounds over the contract life.

Purely Energy supports clients on bill audits where power factor, reactive demand, and capacity-band selection get reviewed together against half-hourly data. The conversion between kVA and kW is the foundation of that review, and the conversations usually end with either a PFC project that pays back inside 12 months, an MIC adjustment that drops standing charges, or both. Either way, the maths starts here. The portfolio-level version of the same audit, across a 20 or 50-site estate, frequently surfaces six-figure annual savings that the previous broker never bothered to look for.