Power and energy describe different things
Watts describe a rate of energy use. Kilowatt-hours describe energy consumed over time. A 1,000-watt device running for two hours uses 1,000 W × 2 hours ÷ 1,000 = 2 kWh.
That formula is useful only when the watts figure represents the power used during the entered runtime. A maximum or rated nameplate value may describe a limit or a particular operating condition rather than long-term average power.
Cycling changes the average
Refrigerators, air conditioners, heat pumps, and other controlled loads can cycle on and off. Variable-speed equipment can change power continuously. Treating a maximum watts figure as continuous draw can overstate energy use.
When an annual kWh figure based on a standardized procedure is available, use the annual-kWh mode for a label repricing task. For a watts calculation, prefer measured average power or measured energy across a representative period.
Label your assumption
The watts mode annualizes the use pattern you enter. It does not infer duty cycle, standby consumption, seasonal operation, or appliance behavior. Keep a note of where the watts and runtime figures came from so the estimate can be reviewed later.