How to Calculate Power Consumption
You can easily calculate the power consumption. To find out the energy consumption by an appliance, you need two pieces of data; the duration of the use of the appliance and the watts consumed. Almost all appliances are labeled with their average rate of energy usage in some accessible place. Some appliances may show volts and amps. In that case, you can get watts by simply multiplying volts by amps (volts x amp). You can convert the watts into kilowatts by dividing watts by 1000.
Kilowatt = X Watt/1000
If a one 1KW appliance runs for one hour, it consumes 1 kWh of energy. If this appliance runs for an entire day, it consumes 24 kWh. You can calculate the cost of running appliances by simply multiplying power consumption with the rate of energy in your area.
Let us assume that energy cost per KWh is 10 cents.
There are several appliances in your home that draw a larger amount of power, but these appliances are used for short duration, for example, your microwave oven. It might consume 1000 watts, but it runs only for a few minutes. If you microwave a dish in 3 minutes, the microwave runs for only 1/20 of an hour. Let us see how much electricity it consumes:
1 kW x 3 Minutes x 1 hour/60 = 0.05kwh
Cost of running the appliance = 0.05kWh x $.10/kWh = $0.005