Calculate daily, monthly and annual power consumption in kWh and electricity cost from appliance wattage (W) and daily operating hours.
Energy Standard: Commercial utility meters bill active energy accumulated over time in kilowatt-hours (1 kWh = 1,000 Watts sustained for 1 hour).
| Electrical Appliance | Rated Power (W) | Real Duty Cycle | Actual Hourly Use |
|---|---|---|---|
| Electric radiator / Thermal emitter | 1.500 W | 65% (Thermostat cycling) | 0.98 kWh |
| Split Air Conditioner (12,000 BTU) | 1.100 W (Inverter) | 55% modulation after cooling | 0.60 kWh |
| Electric water heater tank (80 L) | 1.500 W | 2.5 hours/day | 3.75 kWh / day |
| Induction cooktop (1 medium zone) | 2.000 W | 80% power modulation | 1.60 kWh |
| Combined Refrigerator-Freezer | 120 W (Compressor) | 30% duty cycle over 24h | 0.85 kWh / day |
Multiply appliance power in Watts by operating hours and divide by 1,000: Energy (kWh) = (Watts × Hours) / 1,000.
Multiply daily kWh consumption by the number of days used per month and by your utility electricity rate per kWh.