Newly built homes need an EPC like any other property offered to the market SI 2012/3118, but theirs is produced differently. Instead of an assessor walking round an existing house under RdSAP, a new build is scored under full SAP: the complete calculation, fed with the actual design specification, materials and services of the plot GOV.UK SAP. The developer's SAP assessor lodges it as part of building control sign-off, before handover.
Predicted versus as-built
Buy off-plan and you will see a predicted energy assessment: the score the design should achieve, computed before the house exists. The final, lodged EPC is the as-built version, updated for what was actually constructed. The two normally agree closely; where they differ, the as-built certificate is the one with legal life. If you are buying, ask which one you are looking at.
Why new builds land in band B
Current building regulations demand fabric and services performance that translates, under SAP, to scores clustered in the 81 to 91 range: band B GOV.UK SAP. Reaching A generally requires photovoltaic generation on top of a compliant fabric, which developers fit on some plots and not others. The band B page and band A page cover what separates them.
The certificate ages like any other
A new build's EPC lasts the standard 10 years. When it expires, any renewal assessment happens under RdSAP as an existing dwelling, not full SAP; the EPC vs SAP page explains the two methodologies, and RdSAP 10 explains why a renewal can land differently from the original score. From October 2029 the calculation engine itself changes to the Home Energy Model.