BE24022 - Energy Performance Certificate Accuracy Analysis

Descriptions

**Please note this is an award notice, not a competition. This contract has been awarded via the Crown Commercial Services - RM6126 - Research and Insights .** The Department for Energy Security and Net Zero has a requirement to appoint a supplier to to conduct a systematic analysis of measured energy demand compared to modelled energy demand from the models behind EPCs ((Rd)SAP - Standard Assessment Procedure, current, proposed (HEM - Home Energy Model) and historic versions). Summary of Requirements The project seeks to disaggregate the so-called 'performance gap' with respect to EPC predictions and real energy demand. Here we take a general view of performance gap as any deviation in real world energy demand from that predicted, both over and under estimation. This research seeks to define ways to improve EPC accuracy both through (Rd)SAP/HEM (Reduced dataset Standard Assessment Procedure/Home Energy Model) methodology development and the EPC metric workflow (from EPC commissioning, SAP data input to lodging of the certificate) to support more accurate and trustworthy EPCs. The research will identify systematic sources of bias and error in the way EPCs are created to inform the SAP methodology (such as default values) and home survey process. The sources of error which will be considered are listed below, although this is not an exhaustive list and the research will consider other sources which arise during the course of the research. The analysis will, through statistical comparison and regression analysis, determine the model and process parameters that influence the discrepancy in modelled vs measured energy demand. This is distinct from a limited model sensitivity analysis of SAP which has been carried out and reported in the literature, since it will address the sources of variation of inputs together with the subsequent processing of data through the models.This can be shared with the successful supplier. Aims and Objectives of the Project In summary, the main research questions to address are: -How have historical changes to the (Rd)SAP methodology impacted the accuracy of EPCs? -How does the model, process (RdSAP vs SAP), motivation of assessors (e.g. for re-sale, rental or grant scheme) and the use of defaults impact the accuracy of EPCs? -How do assumptions and modelling of internal temperature impact the accuracy of EPCs? -What additional factors significantly influence the accuracy of EPCs? Due to the recent consultation on and release of the code for the Home Energy Model (HEM) the project should consider the HEM model in the analysis and answering of the research questions in inform its use in the future EPC process.