There is considerable global effort being made towards identifying ways of reducing energy consumption to cope with growing demands. Although there is potential for energy saving in many sectors, our focus is on reducing energy consumption in residential homes. We have developed a system which combines home automation and energy usage monitoring technologies. The system offers a range of tools designed for mobile devices to assist users with monitoring their energy usage and provides mechanisms for setting up and controlling home appliances to conserve energy. In this paper we describe our system and a user study we have conducted to evaluate its effectiveness. The findings of the study show the potential benefits of this type of mobile technology.