DEHEMS: A User-Driven Domestic Energy Monitoring System Vasughi Sundramoorthy, Qi Liu, Grahame Cooper, Nigel Linge School of Computing, Science and Engineering Joshua Cooper Hildebrand Ltd London, United Kingdom The University of Salford Salford, United Kingdom v.sundramoorthy@salford.ac.uk jcooper@hildebrand.co.uk Abstract—Persuasive energy monitoring technology has the potential to inspire sustainable energy lifestyles within the home. However, to effect positive ecological behaviour change, a more user-driven approach is needed for the development of the technology, where the design needs to be accompanied by study on user behaviours and motivations, and the prototype deployed and tested on large sample sizes to understand user preferences. We present DEHEMS, a wide-scale energy monitoring system that undergoes three cycles of design, development and usability assessment so that it can help facilitate energy literacy and environmental awareness based on user preferences. Through real-world deployment, survey and focus group studies carried out in the UK, we present motivations and constraints for saving energy, user assessment of the DEHEMS pilot system and identify some critical user expectations and concerns. We describe how the usability analysis is then incorporated into the design of the next generation DEHEMS system and demonstrate that the resulting system achieves 8% reduction in energy consumption within the first week of feedback. Keywords-energy monitoring, persuasive technology, pervasive computing, human computer interaction, user-driven design, evaluation / methodology, energy feedback I. INTRODUCTION Simple energy saving steps in the home have the potential to reduce 10% of the UK’s carbon emission level, where domestic energy consumption accounts for 30% of the nation’s total CO2 output. Analysis by Darby [1] on smart metering that provides real-time feedback on domestic energy consumption shows that energy monitoring technologies can help reduce 5% to 15% of energy usage. Fischer [2] finds the most successful energy usage feedback are those that are given frequently and over a long time, provides an appliance- specific breakdown, are presented in a clear and appealing way, and use computerized and interactive tools. However, the design and development of energy sensing and display technologies tend to bring the user into the loop after the design is completed, rather than including users during the design process. Fischer points out that research into this area lack large-scale deployment and needs to be accompanied by a body of study on user behaviours, motivations and preferences. Fitzpatrick and Smith [3] assert that there is a lack of argument on the design principles and rationale behind the development of most commercial energy monitoring gaps systems. The aim of the DEHEMS project is to plug these gaps by undertaking a large-scale deployment, where the system development applies three ‘cycles’ of User Driven Innovation methodology [4] for assessing and gathering user motivations, constraints and preferences in each cycle, so that the end product can provide a higher usability value and hence effect positive behaviour change in domestic energy consumers. In this paper, we describe the pilot Cycle 1 system, the results of the user analysis via surveys and focus groups, and the subsequent Cycle 2 system driven by the user requirements from Cycle 1. The paper is organized as follows. Section II describes the DEHEMS development and user assessment methodology. Section III briefly presents the DEHEMS Cycle 1 architecture and user interface. Section IV presents user behavioural context in terms of motivations and constraints for saving energy. We then proceed to discuss the usability analysis. In Section V, we describe the Cycle 2 architecture driven by the usability assessments, and some preliminary results before we conclude our findings in Section VI. II. DEHEMS METHODOLOGY The objective of DEHEMS is to integrate and test the effectiveness of innovative persuasive strategies delivered via an intelligent electronic system infrastructure that is able to infer and reason the energy behaviour of the households, received from a number of different sensing technologies; (1) electrical mains circuit sensing, (2) individual appliance- level sensing, (3) gas mains sensing and (4) ambient sensing such as temperature. DEHEMS integrates and tests the effectiveness of the following persuasive strategies: Multi modal user interfaces: PC-based website, a dedicated real-time energy display device and ubiquitous interfaces such as digital photo frames and mobile phones. Data visualisation: Feedback of energy consumption via graphical information, colour coded alerts, textual tips and alerts, and emotionally engaging narrative pictures that reflect the state of the household’s and the neighbourhood’s energy usage. 978-1-4244-7414-1/10/$26.00 ©2010 IEEE