Patent ID: 8587452

Claim:
A method of synchronizing a time period over which energy measurements are accumulated for an energy monitoring system including a plurality of energy monitoring devices, wherein the time period comprises a time interval at a predetermined time, the method comprising: (a) transmitting a first radio frequency packet from a time reference device via at least a first and a second of said plurality of energy monitoring devices to a third of said plurality of energy monitoring devices; (b) transmitting a second radio frequency packet containing a current time of said third energy monitoring device to said time reference device via at least said fourth and fifth energy monitoring devices; (c) calculating a time difference between said current time and a reference time of said time reference device; (d) updating said current time of said third energy monitoring device when said time difference exceeds a minimum time difference; (e) accumulating, over said time period, a measure of energy consumption by said third energy monitoring device of a load coupled with said third energy monitoring device; (f) transmitting said measure of energy consumption for said time period from said third energy monitoring device via at least a fourth and a fifth of said plurality of energy monitoring devices to a data aggregation device; and (g) identifying by said data aggregation device an aggregate measure of energy consumption consumed by said load over said time period.