A method of determining the utility consumption of each appliance in a collection of appliances by using periodic measurements of aggregate utility consumption of all appliances in the collection, is disclosed. The method comprises of determining the normal utility consumption of various modes of each appliance, fixing a measurement interval, and then measuring aggregate utility consumption at periodic intervals. In each interval, we first determine if the change in aggregate utility consumption in an interval is due to change in status (ON or OFF) of one of the appliances. Otherwise we determine if the change in aggregate consumption is due to a change in status of a pair of appliances. Otherwise, we determine if change in aggregate consumption is due to change in status of a triplet of appliances.