1 Purchase a power meter online. Also called a watt meter or kilowatt
meter, this device measures the actual power your appliance uses. This is typically more accurate than using
the appliance's label info. If you're familiar with electrician's tools, you may be able to use a
multi-meter instead. This requires access to the appliance's wiring while it is plugged in. Needless to say, don't
disassemble anything unless you know what you're doing.
2 Plug the meter between the outlet and the appliance. Plug the power
meter into the wall. Plug the
appliance into the power meter.
3 Measure the kilowatt hours. Set your power meter to display
kilowatt hours. As long as you keep the power meter connected, it should calculate the total kilowatt hours of the
attached appliance. If your power meter only measures watts, you can divide them by 1000 to
calculate kilowatt hours from that measurement. Refer to the power meter instructions if you're not sure how to change its
settings.
4 Use the appliance as you would normally. The longer you leave the
power meter plugged in, the more accurate its calculation will be.
5 Find your monthly or annual kilowatt hours. The kilowatt hours
displayed on the meter is a running total from the time the device was plugged in. You can multiply this number to
estimate your kWh over a longer time period.
For example, let's say the meter has been running for 5 days, and you want to
find the 30-day estimate.
30 divided by 5 is 6, so multiply the kWh displayed by 6.