A paradigm for modelling and analysing Home Automation Systems is introduced, based on Multi-Agent System theory. A rich and versatile environment for Home Automation System simulation is constructed for investigating the performances of the system. The exploitation of limited resources (electricity, gas, hot water) depends on behavioural parameters of the individual appliances. In order to deal with the problem of developing systematic design and validation procedures for control strategies, global performance indices for the system are introduced. Different strategies for allocating resources and establishing priorities in their use can therefore be tested and compared.