The future, viewed from the present, is not a realm of facts (Jouvenel, 1967), but of possibilities, potentials and expectations that shape the present (Borup, Brown, Konrad, & Van Lente, 2006). It has therefore been argued that social technology assessment requires critique of the socio-technical imaginaries through which visions of future technologies are constructed (Simakova & Coenen, 2013). Technology assessment thus moves beyond weighing risks against benefits, and towards interrogating the ‘worlds’, including social relationships, practices and forms of life, that are implicated in future imaginaries (Macnaghten & Szerszynski, 2013). The contribution that qualitative social science research can make here by exploring the meanings of technologies within everyday practices has been demonstrated by, for example, Yolande Strengers’ ethnographic work on everyday energy use and imaginaries of ‘smartness’ (Strengers, 2013). In this paper, and contrasting with Strengers’ ethnographic approach, we show how the biographical investigation of everyday life can be used to develop deliberation on socio-technical imaginaries. Using a novel combination of narrative interviews and multimodal methods, the Energy Biographies project at Cardiff University has examined imaginaries of smartness through the lens of biographical experiences of transformations in how energy is used domestically. In particular, this approach can open up a critical space around future socio-technical imaginaries by exploring the investments that individuals have in different forms of engagement with the world, along with the relationship between these forms and particular technologies. Using a psychosocial framework that also draws on theoretical resources from science and technology studies, we show how these investments can lead to shifts in the meaning of taken-for granted assumptions about the meaning of concepts like convenience, and how valued forms of subjectivity may be conceptualised as emerging out of the ‘friction’ of engagement with the world. In this way, we demonstrate the value for of ‘thick’ data relating to the affective dimensions of subjective experience for social technology assessment.