Energy Statement or a Part L compliance report
Both documents come out of the same modelling software and serve different regimes. Here is what a planning energy statement must demonstrate, why SAP outputs are not predictions, and how to avoid contradicting yourself.
These two documents look similar and answer to different masters. A Part L compliance report demonstrates that the building meets the Building Regulations, assessed by building control and expressed as a comparison against a notional building. A planning energy statement demonstrates that the proposal meets development plan policy, assessed by the planning authority and expressed against whatever baseline that policy sets. The energy statement versus Part L compliance confusion costs architects time because the two use the same modelling software and reach different conclusions from it.
Compliance modelling against a policy document
Approved Document L sets the regulatory standard. For dwellings the assessment runs through SAP, producing a primary energy rate, a carbon emission rate and a fabric energy efficiency rate, each compared against a target derived from a notional building of the same geometry. For other buildings the equivalent runs through SBEM.
Compliance is binary. The building either meets the targets or it does not, and building control signs off on the as-built submission rather than the design stage calculation.
A planning energy statement is argumentative rather than binary. It explains the energy strategy, shows the reduction achieved against the baseline the policy specifies, and justifies the choices made. Where the policy sets a percentage improvement, the statement has to demonstrate it. Where the policy requires an energy hierarchy to be followed, the statement has to show that fabric measures were exhausted before renewables were counted.
So the question each document answers is different. Does this building comply? Against: does this proposal accord with the development plan?
What a planning energy statement must demonstrate
Most policies ask for four things, whatever words they use.
The strategy itself, usually structured as the energy hierarchy: reduce demand, supply efficiently, use renewables, then monitor. In London that is the Be Lean, Be Clean, Be Green, Be Seen sequence set out in the London Plan and the Greater London Authority's energy assessment guidance, with a reporting spreadsheet to match.
The reduction achieved, expressed in the units the policy uses. A policy requiring a 35 per cent on-site reduction beyond the Building Regulations needs the figure calculated on the policy's own baseline, not on whichever baseline the software defaults to.
The feasibility assessment for low carbon and renewable technologies, with reasons where a technology has been discounted. Discounting air source heat pumps on a flatted scheme needs an acoustic or spatial reason, not a cost assertion.
And the overheating position, which is where the energy strategy and the ventilation strategy collide. A fabric-first approach with large south glazing can meet the energy target and fail the overheating test, which is why the choice between TM59 modelling and the Part O simplified method belongs in the same conversation.
Why SAP and SBEM outputs are not predictions
This is the point that causes the most trouble with planning officers, and it is worth being plain about in the statement itself.
SAP and SBEM are compliance tools. They use standardised occupancy, standardised heating patterns, standardised internal temperatures and standardised hot water demand, because the comparison with the notional building only works if both sides use the same assumptions. The output is a compliance metric, not a forecast of what the building will consume.
That has two consequences. A SAP figure should never be presented to a planning authority as predicted energy use or predicted bills. And a policy that sets a target for actual consumption, such as an energy use intensity figure, cannot be demonstrated with a SAP output at all, because SAP does not calculate it.
Where a local policy sets an energy use intensity target, it will usually require a separate predictive model. Say so in the statement rather than offering the compliance figure and hoping.
Local policy percentages and their baselines
| Policy wording | Baseline it implies | Where the ambiguity sits |
|---|---|---|
| Reduction beyond Part L 2013 | The superseded standard | Policy adopted before the 2021 uplift |
| Reduction beyond current Building Regulations | Approved Document L 2021 | Whether the 31 per cent uplift is already counted |
| On-site carbon reduction percentage | The notional building for the relevant edition | Whether offsetting counts towards the figure |
| Energy use intensity target | Predicted consumption | Needs a model SAP does not provide |
| Net zero carbon in operation | Varies by policy definition | What the policy counts as in scope |
The 2021 edition of Approved Document L was set at a 31 per cent reduction in carbon emissions for new homes against the 2013 standard, and 27 per cent for other buildings. Policies written before June 2022 that require a percentage improvement on Part L were drafted against the older baseline, so applying them literally to the current standard can produce either a trivial requirement or an impossible one.
Resolve it in pre-application correspondence and record the answer. A statement that states its baseline, cites the policy it is answering and shows the arithmetic will survive an officer changing their mind about which baseline applies. One that reports a single percentage without saying what it is a percentage of will not.
The Future Homes Standard will change this again. It has been announced and the detail of the final standard and its transitional arrangements needs checking at write time rather than assumed, and as at October 2026 any statement relying on it should say so and give its own date.
Design stage against as-built evidence
Part L works in two stages. A design stage calculation supports the building notice or full plans submission, and an as-built calculation is produced on completion and submitted to building control, along with the energy performance certificate.
Planning works differently. The energy statement is assessed before permission, and whether anything is checked afterwards depends entirely on the conditions attached. Some authorities condition a post-construction report demonstrating that the approved strategy was built. Many do not.
Where there is no verification condition, the statement is still binding in the sense that the permission was granted on it, and a material departure is a change requiring consideration. The distinction between what binds you and what merely advises you is worth getting right, as a planning condition or an informative on the decision explains.
Conditions that require each document
The two documents attract different conditions, and the wording matters.
A condition requiring compliance with Approved Document L is unnecessary and should be resisted, because the Building Regulations apply regardless and the condition duplicates a separate statutory control.
A condition requiring the development to be built in accordance with the approved energy statement is normal and reasonable. So is a condition requiring details of the renewable installation before the relevant part of the works, and a condition requiring a post-construction verification report where local policy provides for it.
Watch for conditions that require a figure the statement did not calculate. A condition requiring an energy use intensity to be achieved, imposed on a scheme assessed only through SAP, is a condition you cannot evidence compliance with.
Avoiding contradictions between the two
The commonest failure is a mismatch between the specification in the planning Energy Statement and the specification in the SAP model.
Three checks catch most of it. Confirm that the renewable capacity claimed in the energy statement is the capacity entered in the compliance model, including panel count and orientation. Confirm that the fabric values quoted in the planning documents match the model inputs, element by element. And confirm that the heating system described in the planning statement is the system modelled, because a change from a gas boiler to a heat pump between planning and building control changes both the carbon figure and the overheating result.
Then keep the Sustainability Statement consistent with both. Three documents quoting three different window U-values is the kind of inconsistency that produces an officer query in week seven and a revised submission after that. The relevant report types sit in the energy and sustainability group of the report index.
This is general guidance, not legal advice; check the position with your local planning authority 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.
Frequently asked questions
Is a SAP calculation the same as a planning energy statement?
No. A SAP calculation demonstrates compliance with Approved Document L against a notional building, and building control assesses it. A planning energy statement demonstrates accordance with development plan policy, explains the energy strategy and shows the reduction achieved against the baseline that policy sets. The energy statement normally uses SAP outputs as evidence.
Can I present a SAP figure as predicted energy use?
No, and officers increasingly know it. SAP and SBEM use standardised occupancy, heating patterns and temperatures so that the comparison with a notional building is valid. The output is a compliance metric rather than a forecast. A policy expressed as an energy use intensity target needs a separate predictive model.
Which Part L baseline does a percentage policy refer to?
It depends when the policy was adopted. The 2021 edition of Approved Document L was set at a 31 per cent carbon reduction for new homes against the 2013 standard and 27 per cent for other buildings. Policies written before June 2022 were drafted against the older baseline, so resolve the point in pre-application correspondence and record the answer.
Can the council condition compliance with Part L?
It should not. The Building Regulations apply regardless, so a condition requiring compliance duplicates a separate statutory control and fails the necessity test. A condition requiring the development to be built in accordance with the approved energy statement is different and is normal practice.
What usually goes wrong between planning and building control?
A specification mismatch. The renewable capacity claimed in the energy statement differs from the capacity in the compliance model, or the fabric values differ element by element, or the heating system changes from a boiler to a heat pump after permission. Each of those changes the carbon figure and sometimes the overheating result.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.