Energy assessor accreditation for planning stage work

SAP assessor accreditation matters at planning stage for a reason that catches practices out later. The energy statement submitted with a planning application is usually built on the same calculation engine that will eventually produce the compliance evidence and the energy performance certificate, and only an accredited assessor can lodge those outputs. If the planning stage numbers came from someone outside an accreditation scheme, they cannot be carried through.

Nothing in the planning system requires the author of an energy statement to be accredited. Building control does require it, and the gap between those two positions is where projects lose time.

Why accreditation matters before building control

An energy statement at planning stage is a policy document. It shows the carbon reduction the scheme will achieve against the relevant baseline and explains how, usually following the fabric first sequence that reduces demand before supplying it more cleanly.

The calculations behind it are the same calculations used for Part L compliance. Where the planning submission uses an approach, a software version or a set of assumptions that the eventual compliance assessor would not use, the design has to be reworked once the accredited assessor is appointed.

A council rarely asks who prepared the statement. The Greater London Authority and boroughs applying London Plan energy policy look more closely, because the reporting requirements are prescriptive and the figures are monitored after completion.

The practical risk is not planning refusal. It is discovering at technical design that the 31 per cent improvement quoted in the planning statement is not achievable with the specification the client has priced.

Domestic and non-domestic accreditation routes

Domestic new build uses the Standard Assessment Procedure. The person producing compliance calculations and the energy performance certificate for a new dwelling is an on construction domestic energy assessor, accredited through a government approved scheme and subject to its audit and quality assurance regime.

Non-domestic buildings use the Simplified Building Energy Model or, where the building's form or services fall outside its scope, dynamic simulation modelling. Non-domestic assessors are accredited at levels, with the higher levels covering complex buildings and dynamic simulation. A level appropriate to a small retail unit does not cover a mixed use block with a communal heat network.

Match the accreditation level to the building before appointment. The question to ask is not whether someone is accredited, but which scheme, at what level, and whether that level covers the building type and servicing strategy in front of them.

Overheating assessment under Part O is a related but separate competence, and the modelling skills do not automatically overlap. Our note on who can prepare an overheating assessment sets out what to look for there.

Design stage and as-built roles

The same assessor usually performs two distinct roles, and the distinction matters for appointment scope.

Design stage calculations are submitted before work starts. As-built calculations follow completion and reflect what was actually installed, including any substitutions made on site.

Where those two diverge, the as-built figure is the one that counts. Specification changes made for cost during construction, a different boiler, thinner insulation, a change of glazing, all land in the as-built calculation, and a building that fails at that point is expensive to remedy.

Appoint one assessor across all three stages where you can. Continuity is worth more than a marginal fee saving, because the person who set the assumptions is the person best placed to see what a substitution does to them.

Software approval and version control

Calculations must use software approved for the purpose, and approvals are version specific. A calculation run on a superseded version can be rejected by building control even where the inputs are correct.

Two version issues recur on long projects. A scheme designed under one edition of the guidance and constructed under the next, where transitional provisions determine which applies. And a planning application submitted years before construction, where the baseline has moved and the planning stage percentage improvement no longer describes the same comparison.

Record the software name, version and the guidance edition in the Energy Statement itself. It takes one line and it saves an argument at discharge of conditions, when an officer asks whether the submitted figures relate to the current standard.

Where a condition requires a scheme to achieve a stated carbon reduction, check whether the condition is drafted against the edition in force at permission or at commencement. The difference is a real one on schemes with a long lead-in.

Where the consultant is not accredited

Plenty of capable engineers produce energy strategies without holding assessor accreditation, and their work at concept stage can be valuable.

The limits are specific. They cannot lodge an energy performance certificate. They cannot produce the compliance output that building control will accept. And on schemes where the local authority requires the assessment to be carried out by a suitably qualified person, an unaccredited author invites a request for confirmation that costs time to answer.

So the workable arrangement is a strategy by the design engineer, with the calculations run or validated by an accredited assessor, and the statement making clear who did which. Where an AI-assisted draft has assembled the structure and the policy references, the calculation inputs and outputs still have to come from the assessor, and the draft must be reviewed before submission. You can find reviewers through the professional directory.

Checking the outputs before submission

Read the calculation output rather than the summary table. Six checks catch most problems.

1. Does the modelled fabric specification match the drawings and the outline specification, including thermal bridging values rather than default worst case figures.
2. Is the baseline the correct one for the guidance edition being applied.
3. Are the carbon factors the current ones, since changes to factors have moved the relative merits of electric and gas systems substantially.
4. Are unregulated emissions reported separately where the policy requires it.
5. Does any communal or district heating assumption match what the servicing strategy actually proposes.
6. Do the dwelling types modelled represent the range in the scheme, including the worst case plot orientation and the top floor flat.

The last one is the most common weakness in residential energy statements. A sample based on mid floor, mid terrace units produces a comfortable result that the worst plots will not deliver.

Handover to the as-built assessor

Set the handover up at appointment rather than at practical completion. The as-built assessor needs the design stage model, the assumptions register, the specification with any approved substitutions, and evidence of what was installed.

Ask the contractor to notify substitutions as they happen, with the energy consequence checked before the order is placed. That single process change prevents most as-built failures, and it costs nothing except attention.

Browse all 66 report types to see how energy and sustainability documents sit alongside the rest of a submission.

This is general guidance rather than legal advice. Check the position with your local planning authority, your building control body or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.