Energy retrofits in households are an important means of reducing energy consumption and mitigating climate change. However, energy retrofit rates have generally been lower than expected. As a key reason behind non-adoption, the complexity of energy retrofits can be challenging for adopters to handle. In this article, we study how suppliers and retrofit adopters seek to manage the complexity of an energy retrofit purchase. Using interview and mystery shopping data, the article analyses how the complexity is managed through a variety of complexity management devices (CMD) and complexity management strategies (CMS). We identify four complexity management devices, concretizations that help deal with energy retrofit complexity: characterisations, projections, comparisons and references. In addition, we identify four complexity management strategies for managing complexity: pre-exposure, choice simplification, outsourcing and championing. The contribution of the study is in highlighting the role of complexity management in energy retrofits and how CMDs and CMSs are involved in structuring energy retrofit offerings, business models and energy information. This, in turn, provides impetus for developing measures to ease the complexity of adoption.