In this demonstration, we show an energy measurement system that estimates the energy consumption of individual appliances using a wireless sensor network consisting of contactless electromagnetic field (EMF) sensors deployed near each appliance, and a whole-house power meter . The EMF sensor can detect appliance state transitions within close proximity based on magnetic fluctuations. Data from these sensors are then relayed back to the main meter using a low-latency wireless sensor networking protocol, where changes in the total power consumption of the house are used to determine the power usage of individual appliances. The sensors are low-cost, easy to deploy and are able to detect current changes associated with the appliance from a few inches away making it possible to externally monitor in-wall wiring to devices like overhead lights or heavy machinery that might operate on multiple phases of the AC distribution system of the building. Appliance-level energy data provide continuous feedback to end users about their consumption patterns and provide building managers accurate information that can be used to target the most effective update and retrofit strategies.