A method for apportioning usage of a utility in a multi-unit building, the method comprising: (a) measuring total usage of the utility by the multi-unit building using a meter unit to produce total usage measurements over a period of time, the total usage measurements to be apportioned to at least one single unit (104, 106) of the multi-unit building; (b) positioning at least one sensor unit in each of the at least one single units (104, 106); (c) monitoring usage of the utility by the at least one single unit (104, 106) using the at least one sensor unit to produce monitoring data for each of the at least one single units(104, 106); wherein monitoring the usage of the utility by each of the at least one single units (104, 106) comprises: (i) determining a start time for usage of the utility; and (ii) determining a stop time for usage of the utility; (d) receiving the total usage measurements and the monitoring data at a processor unit; (e) correlating the total usage measurements and the monitoring data using the processor unit to generate correlated data, wherein correlating the total usage measurements and the monitoring data comprises correlating the start times and the stop times with the total usage measurements corresponding to the start times and the stop times, such that the correlated data includes the start and stop times correlated with the total usage measurements, representing measurements of individual consumption; (f) apportioning the total usage measurements to each of the at least one single units (104, 106) using the processor unit based on the correlated data. (a) measuring total usage of the utility by the multi-unit building using a meter unit to produce total usage measurements over a period of time, the total usage measurements to be apportioned to at least one single unit (104, 106) of the multi-unit building; (b) positioning at least one sensor unit in each of the at least one single units (104, 106); (c) monitoring usage of the utility by the at least one single unit (104, 106) using the at least one sensor unit to produce monitoring data for each of the at least one single units(104, 106); wherein monitoring the usage of the utility by each of the at least one single units (104, 106) comprises: (i) determining a start time for usage of the utility; and (ii) determining a stop time for usage of the utility; (i) determining a start time for usage of the utility; and (ii) determining a stop time for usage of the utility; (d) receiving the total usage measurements and the monitoring data at a processor unit; (e) correlating the total usage measurements and the monitoring data using the processor unit to generate correlated data, wherein correlating the total usage measurements and the monitoring data comprises correlating the start times and the stop times with the total usage measurements corresponding to the start times and the stop times, such that the correlated data includes the start and stop times correlated with the total usage measurements, representing measurements of individual consumption; (f) apportioning the total usage measurements to each of the at least one single units (104, 106) using the processor unit based on the correlated data.