How electricity consumption is calculated
We divide watts by 1,000 to get kW, multiply by hours of use and the load factor, then apply the price per kWh.
W ÷ 1,000 × hours × load factor × price per kWh
Rated power and real consumption
Many appliances do not run at full power all the time. Refrigerators, water heaters and climate equipment cycle or modulate, so the load factor improves the estimate.
How to compare two models
Calculate each appliance separately and combine annual running cost with purchase price, maintenance and expected life.