Abstract: This system is of the power management type and is for controlling the operation of the various stages within a number of units such as heating, ventilation, and air conditioning units commonly referred to as HVAC units which may be of conventional design and for use in commercial buildings.The system permits only a limited number of stages, fewer than the total number contained in all the HVAC units to be predeterminedly operated at one time but preferably stores an indication of all stages which are demanding operation of the total number of HVAC units in the building. If a greater number of stages are demanding than the system has been pre-set to operate then an indication of the unsatisfied or inhibited unit or units is stored. If this condition persists for a predetermined period of time such as 5 minutes then the longest running stage, even though it is sill demanding, is dropped or stopped and the longest waiting inhibited stage is satisfied or started.