Cut your electricity cost by finding out what appliances are worth keeping plugged in. Simply connect an appliance to the meter and it tells you the monthly cost. The unit measures consumption by the kilowatt hour, the same way as your local utility company. You can figure out how efficient each appliance actually is and decide if it's finally time to get that new refrigerator, or if your old air conditioner is the power hog you thought. You can calculate your cumulative electrical expense and forecast usage by the day, week, month, or year.