Submetering refers to the function of using additional meters, other than the main meters at the boundary of the building. The purpose of submetering is to identify where utilities are used. Without submetering, there can be no valid basis for operational control and cost allocation. Likewise, there can be no way to verify efficiencies and quantify savings.
In a hotel, submetering of electricity, steam, chilled water, hot water, and cold water are all practiced. The reduced cost of chilled water metering in the past 10 years has made it viable to identify where air conditioning is being used down to the level of individual rooms.
Installing submeters is significantly cheaper when done during construction or major renovation, so decisions about submetering are best made prior to these activities. Consistency of meter readings is generally more important than absolute accuracy.