Budgeting an energy statement and its calculations
An energy statement is priced by the modelling behind it. Here is what drives the fee, which items local policy adds, and how to stop the design team paying for re-runs.
The energy statement cost on a planning application is mostly the cost of calculations, not the cost of writing. A statement for a single house that reuses compliance modelling already being done is a small job. A statement for a mixed-use block, with a target percentage reduction to demonstrate, a communal heating option to appraise and an offset payment to calculate, is several days of modelling by someone who knows the software, and it has to be redone every time the fabric changes.
Budget it as two lines. The modelling, priced per dwelling type or per building zone, and the reporting, priced once. That split also tells you where the money goes when the design moves.
What a planning energy statement actually contains
It is not a building regulations submission. A planning energy statement demonstrates compliance with the local plan policy on carbon and energy, which usually asks for a percentage improvement against the Building Regulations baseline, delivered in a stated order.
The structure that most authorities expect follows the energy hierarchy: reduce demand through fabric and form, supply efficiently, then use renewables, and report the outcome. In London the London Plan sets that hierarchy out explicitly with a monitoring stage attached, and boroughs apply it with their own thresholds. Outside London, the requirement sits in the local plan and varies widely, so read the policy before scoping the work.
The statement sets out the baseline emissions, the emissions after each stage of the hierarchy, the resulting percentage saving, the technologies proposed with their assumptions, and any shortfall to be met by a carbon offset contribution. An Energy Statement drafted without the modelling behind it will be treated as an aspiration rather than evidence.
The calculation work behind it
For dwellings, the modelling is done in the approved calculation methodology used for Part L compliance, and for non-domestic space it is the simplified building energy model or a dynamic equivalent. Approved Document L in its 2021 form changed the metrics, adding a primary energy target alongside the emissions target and the fabric energy efficiency target for dwellings, so a statement that only reports emissions is incomplete.
What drives the fee is the number of models. Each distinct dwelling type, orientation and exposure condition is a separate run, and a block with 14 flat types produces 14 models before you have tested a single option. Ask your assessor to price per model and to state how many they intend to run, then check that number against the accommodation schedule yourself.
Options appraisal is the second driver. Testing heat pumps against direct electric, or a communal system against individual units, multiplies the runs. Agree at the outset how many options are in the fee.
Site context adds a third. A constrained urban plot with single aspect flats, deep plans and limited roof area for photovoltaics will need more iterations to reach the same percentage than an open site with dual aspect houses. Ask the assessor for an early view on whether the policy target is reachable at all on the form of development proposed, because that answer is worth having before the planning application is drawn rather than after.
Where local policy adds requirements
Several additions appear regularly and each carries its own cost.
A carbon offset calculation, where the policy allows a shortfall to be met by payment, needs the residual tonnage over a defined period and the council's current price per tonne. The price is set locally and is revised, so use the authority's current published figure rather than a number from a previous scheme.
A whole life carbon assessment is a separate exercise entirely, covering embodied as well as operational carbon to a recognised methodology. Where the policy requires one, a Whole Life Carbon Assessment is priced on the quantity surveying input as much as the energy modelling.
A Sustainability Statement or a BREEAM pre-assessment may also be required, and these overlap with the energy statement without replacing it.
Overheating and ventilation are separate items
Do not let an assessor fold overheating into the energy fee without saying how. Approved Document O introduced two routes, a simplified method with limits on glazing and free area, and dynamic thermal modelling. The dynamic route, usually run to the CIBSE methodology for homes, is a different exercise from the compliance model and takes longer.
The distinction matters commercially because the two pull in opposite directions. Insulation and airtightness improve the energy result and worsen the overheating result, and a scheme that passes both usually needs the two models run together by the same person. Commissioning them separately, from different consultants, at different times, produces a design that fails one of them at technical design stage.
An Overheating Risk Assessment at planning stage is worth having on any single aspect flat scheme, particularly where noise constrains openable windows, because that combination is the one that fails.
As-built verification under condition
Most permissions with an energy condition require something after construction: as-built calculations confirming the design performance was achieved, and in London a monitoring submission at completion and again after a year of occupation. Those are real costs, and they arrive on a project that has usually closed its consultant budget.
Put them in the fee proposal at the start. Ask for the post-construction stage to be priced separately and carried as a provisional sum rather than discovering it during handover.
The other post-permission cost is change. A contractor value engineering the glazing specification or swapping a heat pump manufacturer triggers a fresh calculation, and where the condition fixes the percentage saving rather than the specification, the replacement has to be shown to deliver the same result. Write the condition wording into the contract preliminaries so the contractor knows the constraint exists.
Coordinating with the design team
The single largest avoidable cost is re-running models. Fabric build-ups, glazing specification, window areas, the heating strategy and the ventilation strategy all feed the model, and each change means another run.
A workable sequence:
- Fix the accommodation schedule and identify the distinct dwelling types before any modelling starts.
- Agree the fabric and services strategy in principle with the architect and the services engineer.
- Run a single baseline and one or two options, then take the decision.
- Model the chosen option properly and write the statement.
- Freeze the specification for planning submission, and record it in the Design and Access Statement so later changes are visible.
Where an option appraisal is required by policy, run it once, properly, rather than iterating through the design team's preferences.
Avoiding duplicate assessments
The energy statement, the sustainability statement, the whole life carbon assessment and any BREEAM work share inputs and often contradict each other when written by different people. Nothing irritates a sustainability officer more than a scheme reporting three different floor areas across four documents.
Fix that by setting a single assumptions register at the start: areas by use, dwelling mix, baseline year and edition of the standards, weather file, occupancy assumptions, and the emission factors used. Issue it to everyone producing a document. It costs an afternoon and it removes most of the review comments.
One honest uncertainty. Policy in this area is moving, with the Future Homes Standard and successive changes to the Building Regulations, so the baseline against which a percentage improvement is measured can change between a scheme's pre-application stage and its submission. Confirm the applicable edition with the case officer in writing, and state it in the statement.
See PlanScope pricing if you want a structured first draft of the narrative sections before the modelling comes back. 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.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.
Frequently asked questions
What is the difference between an energy statement and a Part L submission?
An energy statement demonstrates compliance with local plan policy at planning stage, usually a percentage improvement on the Building Regulations baseline delivered through the energy hierarchy. The Part L submission is the building control compliance route. They share calculation software and inputs, but the planning document has to argue policy compliance rather than simply pass or fail.
What drives the fee for an energy statement?
The number of separate models. Each distinct dwelling type, orientation and exposure condition is a separate run, so a block with many flat types costs more before any options are tested. Options appraisal multiplies that again. Ask for a price per model and for the number of models the assessor intends to run.
Is overheating assessment included in an energy statement?
Not usually, and it should be priced separately. Approved Document O offers a simplified route and a dynamic modelling route, and the dynamic route is a different exercise from the compliance model. Because insulation and airtightness improve the energy result while worsening overheating, the two are best modelled together by the same person.
How is a carbon offset payment calculated?
From the residual emissions that remain after the energy hierarchy has been applied, converted to a tonnage over a defined period and multiplied by the authority's price per tonne. That price is set locally and revised periodically, so use the council's current published figure rather than one taken from an earlier scheme in the same borough.
Are there costs after planning permission?
Usually. Energy conditions commonly require as-built calculations confirming that the designed performance was achieved, and some authorities require monitoring submissions at completion and after a year of occupation. Ask for those stages to be priced separately at the outset and carried as a provisional sum rather than found during handover.
How do I stop paying for repeated model runs?
Fix the accommodation schedule and identify the distinct dwelling types before modelling starts, agree the fabric and services strategy in principle, then run one baseline and a small number of options before taking the decision. Freeze the specification for submission and record it in the design and access statement so later changes are visible.
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.