The formula to estimate the amount of energy a specific appliance consumes is:

(wattage X hours used per day)/1,000 = daily kilowatt-hour (kWh) consumption.

To calculate the annual consumption, multiply this amount by the number of days you use the appliance during the year. The annual cost to run an appliance is calculated by multiplying the kWh per year by the local utility’s rate per kWh.