Checkable example
Two 100 W appliances used 5 hours per day for 30 days consume 30 kWh. Another 1,500 W appliance used one hour daily adds 45 kWh. Total: 75 kWh; at an illustrative rate of 0.20 per kWh, energy costs 15.
Using the estimate
EIA distinguishes power (W or kW) from energy over time (Wh or kWh). Its example of a 40 W lamp for 5 hours equals 0.2 kWh. Use input watts, not microwave output power or cooling capacity. Standby use can be a separate appliance entry, without counting the same hours twice.
Use average power or effective operating hours at the stated power. A refrigerator or air conditioner does not draw its maximum power for every hour plugged in.
Not your final bill: excludes fixed charges, taxes, subsidies, tiered or time-of-use rates and appliances not listed. Use a meter to measure actual consumption.
Frequently asked questions
Multiply watts by operating hours and divide by 1,000. For multiple appliances, also multiply by quantity and days, then add the results.
Not necessarily. The compressor cycles. Use effective hours at its stated power or measured average power, without applying both adjustments at once.
No. It estimates energy for the appliances listed and multiplies it by your flat input rate. It does not include other charges or tariff rules.