Commission the right outputs for the planning and building-control stages rather than asking only for “an energy report”. [1] [2] [3]
SAP is a calculation method, not a site test
The Standard Assessment Procedure models a dwelling's energy performance. Government guidance identifies its uses in demonstrating Part L compliance and producing EPCs. Reduced-data SAP is a different assessment approach developed for existing homes; it should not be substituted casually for the new-build assessment. [1]
The design-stage assessment should use the actual proposed construction and services. Part L then requires the completed building's performance to be checked using the as-built information, including the relevant air-pressure test result. Changes to insulation, glazing or services need to be reflected in the final assessment rather than left as the original design assumptions. [4]
A passing calculation does not, on its own, prove that every component was installed as specified. Keep the calculation coordinated with the drawings, product information, construction evidence and commissioning records required by the applicable guidance. [4]
A planning energy statement answers a different question
The planning document explains how a proposal meets the relevant national, London-wide and borough energy policies. Its scope depends on the authority and the development. Westminster, for example, requires an energy statement for major development and identifies the relevant London Plan policies and reporting documents. That is a council-specific published requirement, not evidence that every minor application across London needs the same report. [2]
Where both documents are required, the statement and SAP outputs should describe the same design. A planning commitment to one heating or renewable-energy solution should not disappear from the building regulations package without an appropriate review of the approved scheme.
The EPC is a separate completion and transaction document
Government guidance requires an EPC when building a new property and for the relevant sale or letting process. It describes the current certificate's energy rating, energy-use information and recommendations. Arrange the assessment and certificate for the completed dwelling rather than assuming a preliminary SAP output is the finished EPC. [3] [1]
Use the official address consistently so the certificate can be matched to the correct home. This is particularly useful where construction plot numbers differ from the final council-assigned addresses. [5]
Check the methodology during the 2027 transition
The Future Homes Standard takes effect from 24 March 2027, with transitional arrangements and a separate HRB timetable. The applicable regulatory regime should be established before selecting the calculation specification. [6]
In its update of 8 June 2026, government identified SAP 10.3 as the available approved methodology for the new standard following delay to the Home Energy Model. Check the current approved-methodology position before commissioning the assessment; an announced replacement should not be assumed to have displaced SAP automatically. [1]
EPC reform is also being developed, including a four-metric approach. The government's update of 9 March 2026 moved the target launch to the second half of 2027. That published programme should not be treated as a statutory commencement date. Recheck the approved methodology and certificate framework when the assessment is commissioned. [7]
For higher-risk building work, the relevant Future Homes and Buildings Standards provisions commence on 24 September 2027, subject to separate application-based transitional arrangements. This is separate from the general 24 March 2027 commencement. [6]