Energy Efficiency Retrofit (EER) forms a critical component of strategies to reduce energy demand and is increasingly a source of investment and added economic value. While there is a growing body of literature on the technical aspects of EER, research to date has typically focused on the project or component level, to the detriment of system-wide studies. Understanding the materials and monetary flows within supply chains and the value interactions between stakeholders is vital in optimising the long-term capacity of the sector, and increasing the uptake of EER solutions. This chapter forwards a value approach to modelling retrofit activities, providing an analysis of typical EER materials in construction project supply chains. The reported research demonstrates a novel application of value analysis in the construction industry.