Increasing energy costs and climate change legislation have prompted efforts to reduce energy consumption in hospitals. In addition to technological conservation strategies focusing on building and building services, staff-centred initiatives such as energy awareness campaigns are increasingly considered by NHS Trusts. But hospitals are complex buildings with unique energy requirements and it is unclear to what extent these are influenced by clinical staff and patients. This PhD research aims to improve the understanding of hospital electricity use from an end-use perspective and to determine the theoretical reduction potential from behaviour change for different hospital types and areas.