Human factors are essential in the promotion and success of energy efficiency initiatives in the workplace. The existing literature on the field has demonstrated that ‘one-size-fitsall’ solutions tend to fail because they overlook addressing user diversity and the different motivations to behave proenvironmentally. Thus, accounting for user heterogeneity appears to be a successful approach to improve the accuracy selecting and developing behaviour change strategies for different user profiles and work-contexts. This paper addresses the ideation and design process of an Internet of Things (IoT)-based physical object, a coaster, to foster energy awareness in an office-based workplace. Putting the diversity of users in the centre of the process, the Iotdesign proposal links persuasive principles with user profiles in order to give personalised eco-feedback for each different user type. Insights on the inclusion of user diversity on the Design for Sustainable Behaviour (DfSB) theories are provided after conducting qualitative research to evaluate the relationship between users and the designed interactive coaster.