SPR, working with Energy Efficient Strategies, was engaged by the Department of Climate Change, Energy, the Environment and Water to design and deliver the evaluation of the NatHERS for Existing Homes trial. SPR’s role included evaluating training and workforce readiness, assessment tools and processes, data and workflow management, and the perspectives of the banking and property sectors. The evaluation was undertaken in three stages across the course of the trial, and includes qualitative and quantitative data collection and analysis. The evaluation process provided timely, evidence-based feedback to inform improvements to the tool, associated systems, and delivery processes ahead of and following the program’s launch.