Design feedback interventions for household energy consumption reduction
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 within a design process, with surprisingly little research into understanding the actual impact of the behaviour changing interventions yielded through such investigation. Furthermore, the suitability of evaluation methods and the transferability of evaluation results have seldom been discussed. This paper reports on the findings of a three-year research project within the UK social housing sector, research that aimed to reduce energy consumption within the home through behaviour changing intervention, whilst maintaining occupants comfort levels. A behaviour changing prototype was developed through a 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) Does 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 resulted in an evaluation of unparalleled depth. The function and usability of the design were evaluated with users and against extensive feedback design criteria. In addition, behavioural changes in the intentions and habitual processes of the user and their facilitating conditions as well as sustainability changes in energy consumption and comfort were evaluated against pre-intervention state benchmarks. Fitting within the remit of sustainability, the associated ethical dimensions and impact of this DfSB research were also evaluated. Using data collection methods that included focus groups and user trials, the results of this research project illustrate the success of using this tripartite questioning strategy towards the evaluation of a DfSB strategy led intervention, building a vital knowledge platform for the formalisation of transferable DfSB research and evaluation methods.
The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC) and E.ON UK for providing the financial support for this study as part of the Carbon, Control & Comfort project [EP/G000395/1].