Reactive Energy Converter

How to convert reactive energy units

Enter a reactive energy figure, pick the unit it is in, and pick the unit you want. VARh, kVARh and MVARh update together, matching how meters and utility statements report the quantity.

The volt-ampere reactive hour is the internal base and the ladder is exact powers of 1,000. Turning kVARh into a power factor is arithmetic on your meter readings, not a unit conversion, so it stays off this page.

• Take the kVARh figure from the meter or the bill.
• Type it into the Value box, for example 100.
• Pick the From unit, for example Kilovolt-ampere reactive hour (kVARh).
• Pick the To unit, for example Volt-ampere reactive hour (VARh).
• Divide kVARh by kWh separately if you want the power factor implied by the readings.

Reading the reactive line on a commercial bill

A domestic meter records kWh and nothing else. A commercial or industrial meter usually records at least three registers: kWh for real energy, kVARh for reactive energy, and often a maximum demand in kW or kVA. The kVARh register is the one most people have never had to interpret, because it does not correspond to anything they consumed in the ordinary sense.

Tariffs treat it as a network cost rather than an energy cost. The typical structure sets a threshold, commonly a third to a half of the kWh in the same period, and charges a penalty on the excess. That band corresponds to a power factor of roughly 0.95 down to 0.89, which is why those two numbers appear in so many supply contracts.

• kWh: real energy, the part that did work.
• kVARh: reactive energy, the part that loaded the network without doing work.
• kVAh: apparent energy, the hypotenuse, reported by some meters as a fourth register.

What correcting power factor does and does not save

Installing capacitors reduces the reactive energy the meter records, which removes or shrinks the penalty. It does not reduce the kWh, because the equipment still does exactly the same work. Anyone promising an energy saving from power factor correction alone is describing the wrong register, and the payback calculation should be built on the penalty line rather than on the consumption line.

There is a genuine secondary saving, but it is small and local: lower current in your own cables and transformers means slightly lower resistive losses on your side of the meter. On a large site that can be worth having. On a small one it rarely justifies the equipment by itself, and the penalty is the whole case.