Efergy e2c ct e2 classic wireless electricity home energy monitor efergy e2c ct p the efergy e2c ct e2 is a classic wireless electricity home energy monitor that is simple to install and use the sensor wirelessly sends information about the amount of electricity you are using to the display monitor p p the monitor converts this into kilowatt hours the standard unit which the electricity company uses to charge you this shows how much you are using in the same units that are on your bil