This paper empirically explores the role that mobile devices have come to play in everyday practice, and how this links to demand for network connectivity and online services. After a preliminary device-logging period, thirteen participants were interviewed about how they use their iPhones or iPads. Our findings build a picture of how, through use of such devices, a variety of daily practices have come to depend upon a working data connection, which sometimes surges, but is at least always a trickle. This aims to inform the sustainable design of applications, services and infrastructures for smartphones and tablets. By focusing our analysis in this way, we highlight a little-explored challenge for sustainable HCI and discuss ideas for (re)designing around the principle of 'light-weight' data 'needs'.

To date, research in sustainable HCI has dealt with eco-feedback, usage and recycling of appliances within the home, and longevity of portable electronics such as mobile phones. However, there seems to be less awareness of the energy and greenhouse emissions impacts of domestic consumer electronics and information technology. Such awareness is needed to inform HCI sustainability researchers on how best to prioritise efforts around digital media and IT. Grounded in inventories, interview and plug energy data from 33 undergraduate student participants, our findings provide the context for assessing approaches to reducing the energy and carbon emissions of media and IT in the home. In the paper, we use the findings to discuss and inform more fruitful directions that sustainable HCI research might take, and we quantify how various strategies might have modified the energy and emissions impacts for our participants.

In four university student kitchens over twenty-one days, we captured participants' food preparation activity, quantified the greenhouse gas emissions and direct energy connected to the food and cooking, and talked to participants about their food practices. Grounded in this uniquely detailed micro-account, our findings inform sustainable design for cooking and eating at home and quantify the potential impacts. We outline the relation of the impacts to our participants' approaches to everyday food preparation, the organisation of their time, and the role of social meals. Our technique allows evaluation of opportunities for sustainable intervention design: at the appliance, in the digitally-mediated organisation of meals and inventory management, and more broadly in reflecting upon and reshaping diet.

In many parts of the world, mechanical heating and cooling is used to regulate indoor climates, with the aim of maintaining a uniform temperature. Achieving this is energy-intensive, since large indoor spaces must be constantly heated or cooled, and the difference to the outdoor temperature is large. This paper starts from the premise that comfort is not delivered to us by the indoor environment, but is instead something that is pursued as a normal part of daily life, through a variety of means. Based on a detailed study of four university students over several months, we explore how Ubicomp technologies can help create a more sustainable reality where people are more active in pursuing and maintaining their thermal comfort, and environments are less tightly controlled and less energy-intensive, and we outline areas for future research in this domain.