A system for monitoring usage of electrical power by a structure can include: (a) a current sensor unit configured to be coupled to a portion of a surface of a panel, the current sensor unit having: (a) at least one magnetic field sensor configured to detect a magnetic field generated by one or more main electrical power lines; and (b) a processing unit configured to run on a processor. The current sensor unit can be configured to produce an output signal based on the magnetic field detected by the at least one magnetic field sensor. The processing unit further can be configured to receive the output signal from the current sensor unit and process the output signal to determine one or more parameters related to the usage of the electrical power by the first load in the structure. Other embodiments are disclosed.