In a theoretical and experimental investigation into the thermal performance of stratified hot water stores, a transient three-dimensional finite-volume based model was validated by comparison with measured temperatures from a series of thirty-two experiments in which the inlet velocities, temperatures and initial store stratification profiles were varied. A parametric analysis ascertained the effect of inlet and outlet port locations on store performance for a range of operating conditions. The effects of finite volume size on predicted levels of entrainment and diffusion in the inlet region are reported.