What is the difference between kilowatt and kilovolt-amp?
A kilowatt (kW) is the actual power consumed by electrical equipment, while a kilovolt-amp (kVA) is the total power a generator or circuit must supply, accounting for both real and reactive power.
Kilowatt (kW) and kilovolt-amp (kVA) measure different aspects of electrical power. A kilowatt represents real power, the actual energy an appliance or motor consumes and converts to heat, light, or motion. A kilovolt-amp represents apparent power, the total power a system must handle, combining real power and reactive power (energy that electric fields store and release without doing useful work).
The difference becomes critical for generator sizing. A generator rated at 10 kVA cannot necessarily deliver 10 kW of real power. The relationship depends on the power factor, a ratio ranging from 0 to 1 that indicates how efficiently equipment converts apparent power into real power. Most household loads have a power factor near 0.9 to 1.0, while motors and inductive equipment often run at 0.7 to 0.85. A 10 kVA generator with a power factor of 0.8 delivers only 8 kW of real power.
When sizing a backup generator for a Sanford home or business, electricians reference both ratings. The kVA tells you the generator's total capacity, while the kW rating tells you how much actual work the generator can perform. Ignoring either number leads to undersizing, where a generator appears large enough but cannot power all connected loads reliably. Oversizing on kVA alone wastes money without adding usable capacity. Understanding both metrics ensures the system matches the actual electrical demand.