Design for Sustainable Behaviour (DfSB) is an emerging research area concerned with the application of design strategies to influence consumer behaviour during the use phase of a product towards more sustainable action. Current DfSB research has primarily focussed on strategy definition and selection, with little research into formalising a mature design process through which to design these behaviour changing interventions. Furthermore, understanding the actual sustainability and behavioural impact yielded through such investigations is limited in addition to the suitability and transferability of evaluation methods and results having seldom been discussed. This thesis investigated how DfSB models and strategies can be implemented within a structured design process towards a sustainable change in user behaviour. This was achieved by focussing a case study within the UK social housing sector with the aim of reducing domestic energy consumption through behaviour changing intervention, whilst maintaining occupant defined comfort levels. Following an in depth study of physical and behavioural control mechanisms as well as comfort and energy within the research context, a behaviour changing prototype was developed through an augmented user-centred design process, resulting in a physical manifestation of one specific DfSB strategy feedback; a user agentive performance indicator. In order to evaluate this feedback prototype, an evaluation framework was developed, targeted at the three fundamental questions that arise when faced with the evaluation of a DfSB strategy led intervention: (1) Did the produced design solution function for the specified context? (2) Has the user's behaviour changed as a consequence of the design intervention? (3) Is the change in user s behaviour sustainable? Applying these core questions in practice through focus groups and user trials resulted in an evaluation of unparalleled depth. The findings of this thesis illustrate the success of using this augmented design process and tripartite questioning strategy towards the design and evaluation of a DfSB strategy led intervention, building a vital knowledge platform for the formalisation of transferable DfSB theory, design and evaluation methods.