Using circuit-level power measurements in household energy management systems

The first requirement for any intelligent household energy management system is to be able to accurately measure energy usage in the home. Measuring energy usage is not difficult, however we must decide what to measure. Whole-home energy measurement is cheap and easy to setup because only one sensor is placed where the home connects to the power grid. The collected data can provide useful information for large appliances. However, the only way to monitor the energy usage of smaller devices is to install an energy meter on every device of interest. This creates a very detailed picture of household energy consumption, but requires a lot of additional hardware---one meter per device in the home. This paper explores an alternative, more practical, approach to monitor household energy usage including small devices. Our approach uses circuit-level power measurements and a new method to separate aggregate data into device-level estimates. Our initial evaluation resulted in an average error less than 5:35% for three devices with good response to changing device state. We therefore believe that this approach, coupled with a device-level control system, would create an ideal architecture for the next generation of household energy management systems.