This paper develops some extensions to the statistical approach to the estimation of residential end-use load curves and provides a substantive application of these developments to a sample of households. Importantly, the typical assumption that the coefficients of the appliance dummies are fixed, ignores two important sources of variation: during any particular hour the intensity of use of a particular appliance will vary from household to household; also the dummies indicate only absence or presence of the appliance and do not allow for variations in size or capacity. Our treatment of the coefficients of appliance dummies as random rather than fixed provides a structure for the heteroskedasticity that has been observed in previous studies of this kind. Also included in the analysis is the utilization of other sources of information in particular from direct metering and a sample of diaries. The resultant single equation specifications for individual hours are then pooled and jointly estimated using an SUR structure.