A kilowatt-hour (kWh) measures the energy a 1‑kilowatt circuit delivers over one hour, equivalent to 3,600,000 joules. A kilovolt‑ampere (kVA) is the apparent power of a circuit with 1,000 volts and 1 ampere, and 1 kVA equals 1 kW in purely resistive loads.
To convert energy measured in kWh to a power rating in kVA, you only need to know the duration over which the energy was delivered.
Measure the total time the circuit ran. For example, a circuit operating for 200 seconds.
Divide the time in seconds by 3,600 to get hours: 200 ÷ 3,600 = 0.0556 hours.
Divide the energy in kWh by the time in hours. For instance, converting 0.25 kWh: 0.25 ÷ 0.0556 ≈ 4.50 kVA. This value represents the apparent power required.
In practice, kVA ratings are used for sizing transformers and generators, ensuring the equipment can handle the apparent power demand.
