The difference between one month’s reading and the next is the number of energy units that have been used that billing period. To help you save on your energy bill, smart meters are being installed all over the country. They provide two-way communication between you and your utility company, helping your utility know about events such as blackouts. It allows the utility to maintain more reliable services and can be used with home energy management systems such as web-based tools that your utility provides. They can even allow you to remotely adjust your thermostat or turn appliances off.