An energy statement for a commercial or mixed-use scheme runs on a different engine from a housing one. Instead of SAP, the calculations use SBEM and produce a BRUKL output document, tested against the non-domestic side of Part L. If you are extending, converting or building offices, shops, warehouses or workplaces, this is the compliance route your planning energy statement has to reflect.
This guide explains non-domestic Part L, what BRUKL and SBEM are, how they feed a planning energy statement, and what the incoming Future Buildings Standard means for commercial schemes.
Domestic vs non-domestic Part L
Approved Document L has two volumes: Volume 1 covers dwellings, Volume 2 covers buildings other than dwellings. A block of flats with commercial units at ground floor is assessed under both. The domestic units run through SAP; the commercial floorspace runs through SBEM — the Simplified Building Energy Model — which produces the BRUKL (Building Regulations UK Part L) compliance report.
The principle is the same as for homes: the design is compared against a notional building of the same size and shape built to a reference specification, and it must not emit more carbon (and must meet primary-energy and fabric limits). But the metrics, the software and the reference specification all differ.
What BRUKL shows and why planners want it
The BRUKL output document reports the Building Emission Rate against the Target Emission Rate, the primary-energy figures, and whether each element meets the required limits. For Building Control it is a compliance certificate. For planning, it is the evidence base an energy statement draws on to show the scheme meets — and ideally betters — the Part L baseline before renewables are added.
Most local plans, and certainly London boroughs, expect a commercial scheme to go beyond bare Part L. The current Part L 2021 baseline is the starting point; the energy statement then applies the energy hierarchy on top.
The energy hierarchy for commercial schemes
The same Be Lean → Be Clean → Be Green sequence structures a non-domestic energy statement:
- Be Lean — reduce demand through fabric performance, efficient services, LED lighting, controls and reduced air permeability.
- Be Clean — connect to or make provision for heat networks where they exist, relevant to larger urban and mixed-use sites.
- Be Green — supply the remaining demand with low-carbon technology, typically rooftop solar PV and heat pumps in place of gas.
In London, the scheme must demonstrate on-site carbon savings against the Part L baseline and, where a shortfall remains, make a carbon offset payment — the mechanism set out in the London Plan energy planning guidance. That framework applies to major non-domestic development, not only housing.
The Future Buildings Standard is coming
The non-domestic counterpart to the Future Homes Standard is the Future Buildings Standard. The Government's Building Circular 01/2026 confirmed the direction: from 2027 a renamed Approved Document L — Energy and Greenhouse Gas Emissions — will require substantially lower-carbon new buildings, with the new rules applying to new non-high-risk buildings from 24 March 2027. New commercial buildings will move decisively away from fossil-fuel heating toward heat pumps and on-site renewables.
For anyone designing a commercial scheme now, this matters at planning stage: a building specified around a gas boiler today may look dated against the standard it will be built under. Energy statements increasingly need to show a credible fossil-fuel-free pathway even ahead of the deadline.
Common pitfalls on commercial energy statements
- Treating BRUKL as the whole story. Compliance is the floor; the planning energy statement has to show the hierarchy and the percentage carbon saving.
- Forgetting the mixed-use split. Domestic and non-domestic parts need separate SAP and SBEM runs, then a combined narrative.
- Under-sizing renewables. Rooftop plant, PV area and overshadowing constraints all limit what is achievable — model it, do not assume it.
- Ignoring overheating. Highly glazed commercial space can fail on comfort; coordinate the energy strategy with cooling demand.
How Fortress Associates can help
Our energy statement service produces a planning energy statement for UK schemes — including commercial and mixed-use — with the report ready in minutes and free of charge. It sets the Part L 2021 baseline, works through the full Be Lean, Be Clean, Be Green hierarchy with carbon savings at each stage, and reflects London Plan Policy SI2's 35% target and carbon offset where the scheme is in London. Explore our planning services or contact us to discuss a commercial project.
Sources & further reading
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