Introduction Solar hot water (SHW) experiments in social housing are creating a new model for urban infrastructure and energy provision in the State of São Paulo, Brazil. In a country where 80 per cent of dwellings heat water for showering and 73 per cent rely on electric showers for this purpose (PROCEL/Eletrobras 2007), SHW systems have the potential to provide a significant contribution towards a reduction in greenhouse gas (GHG) emissions, whilst also balancing and optimizing electricity demand patterns. This chapter is based on the experience of the Housing and Urban Development Company (CDHU, Companhia de Desenvolvimento Habitacional e Urbano do Estado de São Paulo) of the State of São Paulo in promoting the use of SHW in its dwellings. Although Brazil’s electricity generation is largely based on hydropower (a renewable energy source), SHW is seen by both the State and the municipality as playing a relevant role in their carbon reduction strategies. However, narratives around the use of SHW are taken beyond sustainability discourses and into the space of social justice and poverty alleviation, as they become pivotal in furthering a discourse on ‘housing with dignity’. The chapter demonstrates how experimentation, through the use of small material agencies of technological objects, serves to interweave climate change as a means through which to address other social concerns in the city.