Not always. Although the 2 units are related, they mean different things and describe different aspects of electricity:
- kVA (kilovoltampere)
This is the unit of apparent power. It combines both active power (energy actually used) and reactive power (energy stored and returned by inductive or capacitive loads, such as motors, transformers or capacitors).
- kW (kilowatt)
This is the unit of active power, which represents the amount of energy actually consumed or converted into useful work (such as lighting, heating or driving machinery).
The power of the meters we install are expressed in kVA.
Power factor
The relationship between kVA and kW is determined by the system's power factor (PF).
- The power factor is a value between 0 and 1 that expresses the ratio between active power and apparent power: kW = kVA × PF.
- With a power factor of 1 (for example, for an electric heater with no inductive or capacitive component), we have : 1 kVA = 1 kW.
With a lower power factor (such as for motors or fluorescent lighting), the active power (kW) is lower than the apparent power (kVA).
To summarise
1 kVA is equal to 1 kW only if the power factor is exactly 1. In other cases, the active power (kW) is less than the apparent power (kVA).