Mitigating climate change requires accelerated upgrades to the energy efficiency of entire housing stocks. Designed to shift homeowner behaviours through dissemination of gadgets like LEDs and solar panels, overly techno-economic public policy approaches have failed to engage with the complex socio-technical landscape within which home energy retrofits take place. Moreover, they have helped create spaces where meanings and values regarding climate change and housing energy efficiency remain fluid and uncertain. As a result, confusion reigns and retrofit targets continue to be missed. This thesis challenges traditional home energy retrofit framings by actively engaging with the daily practices and relations of a complex network of building trades people, energy advisors, designers, consultants and NGOs. The research re-orients home retrofits as an essentially social phenomenon, materially influenced by the tacit know-how, understandings, skills, motivations and materialities of these networked intermediary actors who operate along a complex policy chain between the governed household and governing public institutions. The study proposes that retrofit intermediaries are materially implicated in the evolution of a new home energy retrofit practice, distinct from other practices related to the built environment, not only via their discrete technical products and services, but also via influential intermediation processes of interpretation, translation and negotiation that occur between the often times opposing interests of the homeowner and the policy-maker. Vancouver, Canada, a city with a strong green building ethic, serves as an ideal critical case. Applying a theoretical framework grounded in social practices and intermediary dynamics, this thesis focuses on the daily and mundane practices and relations among retrofit intermediaries. The work contributes to a fuller understanding of how intermediaries knowingly (and unknowingly) work to make sense of fuzzy concepts related to climate change, energy efficiency, and the home, and how in doing so, they can contribute to the construction and conveyance of powerful normative understandings of what these mean for society. It concludes that the taken-for-granted practices of retrofit intermediaries provide a useful unit of study for those interested in reducing emissions from existing homes.