How to Estimate Energy Use & Cost
Since the cost of electricity is determined by the number of kilowatt-hours (kWh) used during a billing period, the first step is to determine your average cost per kWh.
The average cost per kWh is computed this way:
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Average Cost per kWh = $ amount of bill / Total kWh used.
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(Example - .06 = $6/1,000 kWh)
Since the wattage of an appliance (equipment) determines the electrical usage per hour, the second step is to determine the wattage.
The wattage of an appliance is found on the serial plate. But it is possible that the electrical requirements will be expressed in volts and amperes, rather than watts. If so, multiply volts times amperes to obtain the wattage.
Use the formula shown in this example to estimate usage and cost.
A light uses 100 watts and is left on for 15 hours.
To compute the usage:
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KWh use = (100 watts x 15 hours) / 1000 watts = 1.5 kWh.
To find your daily cost for electricity, divide your bill by the number of days in the month.