The goal of this paper is to establish a framework called SMOME for evaluating the marginal utility of adding smart sensing and metering hardware to residential premises, in terms of efficiency improvement (reduction in energy consumption) and economic benefits (reduction in energy cost). In order to isolate the effect of smart home technologies on energy efficiency, it is assumed that no changes are made to the appliances already installed. SMOME is developed for experimenting with different types of hardware architectures. Analysis algorithms suitable to the installed suite of sensing and metering hardware are described, which take into account realistic practical constraints. Validated with empirical appliance-level data, the proposed methodology allows us to perform a cost-benefit analysis of several potential smart home solutions. This analysis is meant to enable home owners to evaluate a priori the real cost saving potential of these solutions, when applied to their home.