An energy statement is a technical planning document that shows how a proposed development will reduce its energy demand and carbon emissions to the level required by building regulations and local planning policy. If your local authority has asked for one — or your scheme sits in London or another area with a carbon-reduction target — this guide explains what an energy statement contains, when you need one, and how the Future Homes Standard reshapes the picture in 2026.
What is an energy statement?
At its core, an energy statement demonstrates that a building will be energy-efficient and low-carbon. It establishes a regulatory baseline, then shows the carbon savings delivered by the design at each stage of the recognised energy hierarchy. It is a planning document — distinct from the Part L compliance calculations you submit at building-control stage, though it draws on the same modelling.
When do you need an energy statement?
There is no single national trigger; the requirement is set locally. You will typically need one when:
- the local plan or a supplementary planning document requires an energy or sustainability statement for your development type;
- the scheme is a major development (often 10 or more dwellings, or 1,000m² or more of floorspace);
- the site is in London, where the London Plan applies a specific carbon target; or
- a validation checklist lists it as a required document.
Smaller schemes and householder extensions often do not need a full statement, though some councils ask for a short energy or sustainability note. If you are unsure, check the local validation list or ask us.
The Part L 2021 baseline and SAP
Most energy statements start from the Part L 2021 baseline, using the SAP 10.2 notional-building method for dwellings. SAP (the Standard Assessment Procedure) calculates a dwelling's energy use and carbon emissions, producing the figures the statement reports against. The Approved Document L sets the compliance standard.
The energy hierarchy: Be Lean, Be Clean, Be Green
The energy hierarchy is the backbone of the statement, and CO₂ savings are calculated at each step:
- Be Lean — reduce demand first through a fabric-first approach: good U-values, airtightness, efficient glazing and low-energy lighting.
- Be Clean — supply energy efficiently, for example via heat networks where available.
- Be Green — meet the remaining demand with low-carbon and renewable technology such as heat pumps and rooftop solar PV.
For London schemes, the London Plan Policy SI2 sets a 35% on-site carbon reduction target beyond Part L, with any shortfall to net zero met through a carbon offset payment to the borough. The GLA energy assessment guidance sets out how this is demonstrated.
The Future Homes Standard in 2026
The direction of travel is steep. In March 2026 the government published the Future Homes Standard, the next revision of Part L for England. It is designed so that new homes are net-zero-carbon ready, with fossil-fuel heating (gas boilers) no longer permitted in new homes from 2027, a much larger requirement for rooftop solar PV, and compliance demonstrated through an updated SAP methodology. Schemes coming forward now should be designed with this trajectory in mind, since heat pumps and generous renewables are becoming the norm rather than the exception. Energy sits alongside wider environmental requirements — for the biodiversity, water and greening side of planning, see our companion piece on sustainability statements.
How Fortress Associates can help
Fortress Associates prepares automated, site-specific energy statements for planning applications across every UK local authority, and the report is free. We build the Part L 2021 / SAP 10.2 baseline, work through the full Be Lean, Be Clean, Be Green hierarchy with CO₂ savings at each stage, and address the London Plan SI2 35% target and carbon offset for London schemes. Start on our energy statement page, get in touch via the contact page, or browse our other services.
Sources & further reading
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