The generation capacity of an electricity network is usually significantly greater than typical demand in order to ensure peaks can be accommodated. Demand response techniques aim to smooth demand by modifying the time of end-users electricity consumption, which may reduce the required total generation capacity. These techniques will become increasingly important in domestic properties as energy intensive devices such as electric vehicles and electric heat pumps become more prevalent, which will likely result in both greater peaks in demand and a larger proportion of flexible demand. The techniques may also have value in the current domestic environment, which already typically contains a number of relatively energy intensive devices and appliances. In the short term, domestic demand response may be achieved through the simple provision of information to occupants to inform them of the best times at which to use energy. However, in order to realise its full potential it is likely that automation will be required to reduce the need for explicit end-user action and allow for real-time responses. In this paper we present a wireless sensor and actuator network that supports the automated demand response of household appliances. The sensors monitor the power usage of enabled appliances and the actuators control those appliances in response to tariffing signals and user requirements. The system was designed to operate in a typical contemporary domestic environment with standard “dumb” appliances and metering. It was installed in 3 domestic properties to control washing appliances in a series of case studies. We detail the technology, system architecture and control strategy required to successfully retrofit and utilise such a system in these case studies.