kW versus kWh: power and energy are not the same question

kW describes power: the rate at which equipment needs electricity at one moment. kWh describes energy: power multiplied by time. A 2 kW heater running for three hours uses 6 kWh. The two units answer different buying and planning questions.

Use kW when capacity matters

Inverters, generators, circuits and electrical supplies must handle simultaneous power. Add the equipment that can run together, then allow for starting surge and manufacturer limits. Use the electrical load calculator for an early planning screen.

Use kWh when duration matters

Electricity bills, solar production and battery energy depend on operating time. A battery may have enough kWh for several hours but still fail if its inverter cannot deliver the needed kW. Estimate appliance runtime with the electricity consumption calculator.

Do not divide a battery label or a solar kW rating into a bill without checking the matching unit. Tariffs are usually per kWh; capacity limits are usually kW.