The central supposition put forward in this paper is that typical building-related energy efficiency measures do not automatically yield the looked-for large-scale environmental effects. Rather, many such measures entail two kinds of reductionism, in that they i) treat buildings detached from the larger system (such as the urban context), to which they belong; ii) concentrate on solutions, which are predominantly technological in nature. As a consequence, the complexity of the challenge may be neglected, along with other non-technical, yet potentially critical areas of concern. Such areas include, inter alia, economy, politics, policy, as well as societal and psychological circumstances. In this paper, we discuss a few typical instances of such reductionist stances to shed light on factors that impede their utility. Moreover, we highlight a few instances of systemic methods that have been suggested as having the potential to address complex problems in general, and the environmental implications of energy efficiency measures in the context of the built environment in particular.