Energy statement evidence a case officer actually checks

A case officer reading an energy statement is not auditing your model. They are looking for four things: a stated baseline, a stated percentage improvement against it, modelling output that supports the number, and a set of commitments specific enough to put into a condition. An energy statement evidence checklist that covers those four will get through validation and through the officer report. One that describes the energy hierarchy for three pages and then asserts a percentage will come back with a request for further information, usually at week six of an eight-week determination period.

The gap between the two is mostly appendices.

What the officer looks at first

Officers go to the summary table. They want the regulated carbon emissions of the compliant baseline, the emissions after fabric measures, the emissions after any low carbon heat, the emissions after renewables, and the residual figure, each in tonnes of CO2 per year with the percentage improvement stated at each step.

If the statement does not contain that table, the officer has to derive it, and most will not. The second thing they check is whether the percentage quoted in the summary matches the percentage in the modelling output appended at the back. A mismatch between the two is the single most common reason an energy statement is sent back.

Then they check the recommendations against the drawings. An officer with a site plan in one hand and an energy statement in the other will notice that the photovoltaic array shown as 120 m² does not fit on a roof that is 90 m² before you allow for the lift overrun.

Baseline, improvement and residual emissions

The baseline is the same building modelled to the notional specification in the current Part L. For dwellings that means the Target Emission Rate, the Target Primary Energy Rate and the Target Fabric Energy Efficiency generated by the approved calculation methodology; for other buildings it means the notional building output from the national calculation methodology. Approved Document L 2021 took effect in June 2022, and the government's own figures for that uplift were around a 31 per cent carbon reduction for new homes and 27 per cent for non-domestic buildings against the 2013 standards.

State which version of the calculation software and which fuel factors you used. Officers in authorities with carbon policies will check that, because a reduction calculated against an older baseline reads as a larger improvement than it is.

The improvement should then be presented in the order of the energy hierarchy, with the fabric contribution isolated. Policies in many authorities, and the London Plan in particular, set a minimum improvement that must come from fabric and passive design before any plant or renewables are counted. Presenting a single blended figure makes it impossible for the officer to confirm compliance, and they will ask.

Where a residual remains and the authority operates a carbon offset fund, calculate the liability and say so. The Mayor's energy assessment guidance has used a nominal price per tonne over a 30-year period, and individual boroughs have since set their own figures, so confirm the current rate with the borough rather than quoting the guidance figure.

Outputs that should be appended

This is where statements thin out. Append the modelling outputs in full rather than summarising them.

For dwellings, that means the as-designed compliance report produced by the approved methodology for each dwelling type, with the dwelling types cross-referenced to the plan numbers. For non-domestic buildings, append the full compliance output from the national calculation methodology, not the first page.

Add the overheating evidence as well. Approved Document O applies to new residential buildings, and where a dynamic simulation has been run, the CIBSE TM59 output belongs in the appendix of the overheating risk assessment rather than being described in a sentence. Officers in authorities with their own overheating policy will look for the weather file used and the internal gains assumed, because those two inputs determine the result.

Where a photovoltaic yield has been claimed, append the yield calculation with the orientation, pitch, shading factor and system losses shown. A yield asserted without a calculation is treated as unevidenced, and an array whose output was calculated at an unshaded southern orientation on a roof that faces east is worse than unevidenced.

Consistency with the drawings and the area schedule

Officers cross-check three numbers more than any others: floor area, glazing ratio and renewable array area.

Floor area should match the area schedule exactly. If the energy model was built from an earlier revision of the plans, say which revision and explain why the difference does not change the conclusion. Glazing ratios in the model should be traceable to the elevations, because a model run at 20 per cent glazing on a scheme drawn at 35 per cent will not perform as claimed.

Thermal bridging is the input most often left at default values, and the one that most often changes the answer once real junction details are calculated. Where accredited construction details or project-specific psi values have been used, name them. The practical consequences of getting this wrong are set out in more detail in the discussion of thermal bridging detail at planning stage.

Renewables sizing and the roof area arithmetic

Do the arithmetic on the roof before you size the array, and show it. An illustrative example for a flat-roofed block makes the point.

1. Start with the gross roof area from the roof plan.
2. Subtract plant, lift overruns, access zones, maintenance walkways, roof lights, green roof and any area within the required edge setback.
3. From the remaining area, allow roughly 5 m² of panel per kWp for current modules, and on a flat roof allow 10 m² to 12 m² per kWp once inter-row spacing is included.
4. Apply a shading factor derived from the surrounding context, including any consented neighbouring scheme.
5. Compare the resulting capacity with the capacity assumed in the model.

Those area figures are a field convention for illustration, not a standard, and the panel data sheet should drive the final number. The reason to show the steps is that an officer can follow them. An array that survives step two and step four is an array that will still be there at as-built stage.

Competition for the same roof is the awkward part. Green roof policy, amenity space, plant, and photovoltaics all want the top of the building, and the energy statement is usually written as though only the panels exist. Draw a roof zoning plan and the objection disappears. Where a heat network connection is the preferred route instead, the case for safeguarding a future connection needs the same level of evidence as an array does.

Commitments that turn into conditions

Everything you promise in an energy statement is a candidate for a condition, and the condition will be drafted from your words. So write the commitment at the level of precision you can actually deliver.

A commitment to install a photovoltaic array of not less than a stated capacity is deliverable. A commitment to achieve a stated percentage reduction as built is harder, because it depends on an as-built calculation with inputs you do not control at planning stage. A commitment to a named product is a problem the first time the supplier changes the model number.

Where a commitment turns out to be undeliverable, the route is an application under section 73 of the Town and Country Planning Act 1990 to vary the condition, with a revised assessment showing the alternative achieves the same outcome. That takes eight weeks and a fee, and it is avoided by drafting with a tolerance in the first place.

The pre-submission checklist

Before the statement goes out, confirm each of the following.

The summary table carries baseline, each hierarchy stage and the residual, in tonnes per year with percentages. The software version and fuel factors are named. The full modelling output for every dwelling type or the whole non-domestic building is appended. Floor areas and glazing ratios match the drawing revision cited. The renewable capacity is supported by a roof area calculation and a shading assumption. Any residual offset liability is calculated at the rate the authority currently applies. And every commitment is written in terms that could be transcribed into a condition without further definition.

A statement that passes that list is a short document with long appendices, which is the right shape. The energy statement report page sets out what the document covers section by section.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required, and the underlying calculations should be produced by a competent energy assessor. You can start from a postcode to see which energy and sustainability reports a scheme is likely to need.