In less than a generation, air conditioning has spread around the world, increasing energy consumption and producing demand where none existed before. How has this come about? This article asks whether transition theories (and the multilevel perspective as an exemplar) are of value in addressing this question and what other approaches might be developed. It is concluded that what seems to be the transnational diffusion of mechanical cooling is best understood as an outcome of multisited processes in which air conditioning is integrated into practices like those of office work, nursing, taking a luxury break or simply living at home. Rather than mapping diffusion across a stable terrain, this perspective argues for a more sophisticated interpretation of how mechanical cooling remakes practices and the places in which they are reproduced. This conclusion has implications for efforts to stem air conditioning and the energy demand associated with it.