How is the ZEB inputted to an EPC?
The ZEB is recognised in the Standard Assessment Procedure (SAP) as an Electric dry core storage boiler, with 100% efficiency when installed in a heated space. However, this classification is based on outdated technology from the 1970s, meaning that EPC scores do not currently reflect the full benefits of the ZEB. Because EPCs are calculated based on running costs rather than efficiency, and they use outdated energy price assumptions, electric heating systems like the ZEB will usually receive a lower EPC rating than gas boilers despite being highly efficient and low-carbon.
We are working to update how the ZEB is recognised in SAP, with the aim of improving its impact on EPC scores. We're aiming for the ZEB to be included in Appendix Q, allowing EPC assessors to better reflect its benefits. Changes are expected by the end of the year, though timelines depend on regulatory processes. In the meantime, homeowners can use our cost and carbon calculator for a more accurate estimate of running costs and emissions.
We are working to update how the ZEB is recognised in SAP, with the aim of improving its impact on EPC scores. We're aiming for the ZEB to be included in Appendix Q, allowing EPC assessors to better reflect its benefits. Changes are expected by the end of the year, though timelines depend on regulatory processes. In the meantime, homeowners can use our cost and carbon calculator for a more accurate estimate of running costs and emissions.