EPC vs energy statement is one of the most common points of confusion for anyone building or extending in the UK — and mixing them up can cost you a validation delay or a failed completion. The short answer: an energy statement is a forward-looking planning document that shows how your scheme will beat carbon targets, while an Energy Performance Certificate (EPC) is a standardised certificate produced when the building is finished (or sold or let). You often need both, at different stages, and they are calculated from the same underlying methodology.
This guide explains what each document does, when each is required, the key differences at a glance, and how the Future Homes Standard is about to change both.
What an energy statement is
An energy statement supports a planning application. Councils use it to check the design complies with their adopted energy policies — which typically go beyond Building Regulations. A robust statement models the dwelling against the Part L 2021 notional building using SAP 10.2, then works through the energy hierarchy — Be Lean (fabric efficiency), Be Clean (efficient supply), Be Green (renewables) — quantifying the CO₂ saving at each stage. In London, Policy SI2 of the London Plan requires major schemes to achieve at least a 35% on-site carbon reduction over Part L, with any shortfall to net zero met by a carbon offset payment; the GLA's energy assessment guidance sets the reporting format. Many councils outside London ask for a proportionate version for new dwellings and larger extensions.
The statement is assessed before permission is granted: it shapes the design. If you are new to the document, start with what is an energy statement and when do you need one.
What an EPC is
An Energy Performance Certificate rates a building's energy efficiency from A (best) to G, with an accompanying environmental impact rating and recommendations. It is a legal requirement under the Energy Performance of Buildings Regulations whenever a building is constructed, sold or let — the rules are summarised on GOV.UK. For a new home, the 'as built' EPC is produced at completion from the final SAP assessment, using the products actually installed, and is lodged on the national register. It lasts ten years.
Where the energy statement is a promise made to the planning authority, the EPC is a record of what was delivered — and building control sign-off depends on the final SAP calculations demonstrating Part L compliance, per Approved Document L.
Key differences at a glance
| Energy statement | EPC | |
|---|---|---|
| Stage | Planning application (pre-consent) | Completion, sale or letting |
| Regime | Planning policy (local plan / London Plan) | Building Regulations / EPB Regulations |
| Purpose | Show the design beats the Part L baseline and meets council targets | Certify the finished building's energy performance |
| Output | CO₂ savings through the energy hierarchy; policy compliance | A–G rating on the national register, valid 10 years |
| Who checks it | Planning officers | Building control; accredited energy assessor lodges it |
How the two connect: SAP runs both
Both documents are built on the Standard Assessment Procedure. The design-stage SAP 10.2 model that powers your energy statement is the same engine that later produces the as-designed and as-built Part L outputs and the EPC. That is why consistency matters: if the planning statement commits to a heat pump, wastewater heat recovery or a set fabric specification, swapping them out during construction can breach a planning condition even where Building Regulations are still met. Councils increasingly condition the approved energy strategy and ask for post-construction evidence.
The Future Homes Standard changes both
In March 2026 the Government confirmed the Future Homes Standard, with new regulations applying to building work from March 2027 (with transitional arrangements). New homes will be designed for roughly 75–80% lower carbon emissions than 2013 standards, with low-carbon heating as the default and solar PV expected on most new homes — and the Home Energy Model will replace SAP as the calculation engine. Planning-stage energy statements and completion-stage certificates will both be recalibrated as a result. Our guide to the Future Homes Standard and energy statements covers what to do on schemes straddling the transition.
Which do you need — and when?
- Applying for planning for a new dwelling or major scheme? Expect to submit an energy statement with the application — check the council's validation checklist.
- Extending a home? Usually no EPC is triggered and only some councils ask for an energy statement; Part L still applies through building control.
- Completing, selling or letting? You need an EPC — the energy statement does not substitute for it.
- Budgeting? EPCs cost tens of pounds; consultant-written energy statements typically cost hundreds — see what an energy statement costs.
How Fortress Associates can help
Fortress Associates provides a free automated energy statement service for UK planning applications — ready in minutes, built on the Part L 2021 / SAP 10.2 notional-building baseline and working through the full Be Lean, Be Clean, Be Green hierarchy with CO₂ savings quantified at each stage. London schemes get Policy SI2 35% target and carbon offset calculations included. See all our planning report services or contact us with questions about your scheme.
Sources & further reading
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