A method is presented for the estimation of a "probable" annual maximum collective demand in kva (kilovolt-amperes) for a set of heterogeneous residential electric appliances. The method considers diversity between appliances of different types as well as diversity among those of the same type. It is based on a probable model of appliance behavior using parameters obtained from observed operation. The accuracy of the method and its application are examined, and representative parameter values are presented but not derived. A sample calculation is included.