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Part L · Non-Domestic · Design & Planning

SBEM Calculations
& BRUKL Reports.

Level 4 & 5 NDEA-accredited energy assessments for new, extended, and refurbished non-domestic buildings. Design stage and as-built BRUKL reports with commercial EPC, delivered within 5 working days.

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The UK government's approved method for non-domestic building energy assessment.

SBEM — Simplified Building Energy Model — is the BRE-developed software methodology approved by the UK government for calculating the energy performance of non-domestic buildings. It is the non-domestic equivalent of SAP, and is required under Part L of the Building Regulations for all new, significantly extended, or materially refurbished commercial buildings.

An SBEM assessment models the building's energy consumption and CO₂ emissions based on its geometry, construction, HVAC systems, lighting, and any renewable energy sources. The output is a BRUKL Report (Building Regulations UK Part L) which demonstrates compliance, and a commercial Energy Performance Certificate (EPC) — both legally required for Building Control sign-off.

SBEM assessments must be carried out by a registered Non-Domestic Energy Assessor (NDEA). Our team are qualified and registered through Elmhurst Energy at Level 4 and Level 5 — covering all standard non-domestic building types up to and including complex HVAC systems, high energy-use buildings, and buildings with district heating.

When is an SBEM assessment required?

All new non-domestic buildings Required for Building Control approval and to produce a commercial EPC before the building is occupied.
Significant extensions Extensions over 100m² or greater than 25% of the existing floor area typically trigger a Part L assessment.
Major refurbishments & change of use Significant works to the building fabric, HVAC, or a change from one use class to another typically require SBEM.
Sale or let of commercial property A valid commercial EPC is required whenever a non-domestic building is sold or let to a new tenant.
Non-domestic buildings
SBEM
  • Offices, retail, education, healthcare, warehouses, mixed-use
  • Assesses HVAC, lighting, fabric, and renewables
  • Outputs BRUKL Report (Part L compliance) and commercial EPC
  • Must be carried out by an NDEA Level 3, 4, or 5 assessor
  • Uses iSBEM or accredited dynamic simulation software
vs
Domestic buildings
SAP
  • Houses, flats, apartments, and residential conversions
  • Assesses fabric, heating, hot water, and renewables
  • Outputs Predicted Energy Assessment and residential EPC
  • Must be carried out by an OCDEA assessor
  • Uses Elmhurst SAP or equivalent accredited software
Both produce an EPC — the certificate that shows the building's energy rating. SBEM and SAP are the assessment methods; the EPC is the output. Build Envelope are accredited for both.

Every non-domestic building type covered.

Our Level 4 and 5 NDEA accreditation covers the full range of non-domestic building types, from simple single-zone offices to complex mixed-use schemes with district heating.

Offices
New build, fit-out, and refurbishment. All HVAC system types including VRF/VRV, chilled beam, and underfloor heating.
Retail & Commercial
High street, out-of-town retail, restaurants, leisure centres, and mixed-use ground floor commercial.
Education
Schools, colleges, and university buildings. DfE and local authority-funded developments assessed to current standards.
Healthcare
GP surgeries, dental practices, care homes, and NHS-funded clinical buildings with complex ventilation requirements.
Warehouses & Industrial
Distribution, storage, and light industrial. Roof lighting, radiant heating, and process energy assessments.
Mixed-Use & Other
Hotels, sports facilities, community buildings, and mixed residential and commercial schemes requiring SBEM and SAP.

SBEM certification happens at design stage and as-built.

Both stages are required for new build and significant extension projects. Early engagement at design stage avoids costly changes later in the programme.

01
Before construction
Design Stage BRUKL Report

Carried out before construction begins. We build an energy model of the proposed building using the architectural drawings and engineering specifications, demonstrating that the design meets the Part L Building Emission Rate (BER) targets.

  • Review of drawings, specifications, and engineering information
  • Input of building geometry, fabric U-values, and G-values into SBEM software
  • Modelling of HVAC systems, lighting, and any renewable energy sources
  • Calculation of Building Emission Rate (BER) vs Target Emission Rate (TER)
  • Issue of Design Stage BRUKL Report for Building Control submission
  • Advice on specification changes to improve the rating or reduce build cost
02
After construction
As-Built BRUKL Report & EPC

Once construction is complete, the SBEM model is updated to reflect the building as actually built — incorporating any specification changes, final product data, and air tightness test results. The as-built report is required to issue the commercial EPC.

  • Update model to reflect any changes from the design stage specification
  • Input of actual air permeability result from pressure test
  • Incorporation of final HVAC, lighting, and controls product details
  • Final SBEM calculation confirming as-built compliance
  • Issue of As-Built BRUKL Report and commercial EPC
  • Submission to Building Control for completion sign-off

From drawings to BRUKL report — what to expect.

A coordinated, structured approach from first enquiry through to certification. We keep you informed at every stage and manage Building Control queries on your behalf.

01
Initial consultation
We discuss the project scope, building type, HVAC strategy, and programme. We confirm which level of NDEA accreditation is required for your building and provide a fee proposal.
02
Information gathering
We request drawings, specifications, and engineering information in a structured way — prompting for each item at the right time to keep the process moving without overwhelming your design team.
03
Modelling & calculation
The building is modelled in approved SBEM software. We calculate the BER, review the result, and advise on any specification changes needed before producing the formal report.
04
BRUKL Report & EPC issued
Design stage BRUKL Report issued within 5 working days. As-built report and EPC issued promptly after construction, following receipt of final specification data and air tightness results.

The information required to carry out an SBEM assessment.

The more complete the information provided at the outset, the faster and smoother the assessment. We're happy to work from early-stage drawings and refine as the design develops.

Architectural drawings
  • Floor plans for all levels (with room names and areas)
  • Elevations showing window and glazed area positions
  • Sections and roof plan
  • Building orientation (compass bearing)
  • Details of any atriums, rooflights, or skylights
Building fabric
  • Wall, roof, and floor construction specifications
  • U-values for all opaque elements (or build-up details)
  • Window and glazed door U-values and G-values (solar heat gain coefficient)
  • Air permeability design target (or test result for as-built)
  • Thermal bridging details / PSI values where applicable
HVAC & building services
  • Heating system type, fuel, and efficiency (SCOP, CoP, or seasonal efficiency)
  • Cooling system type and SEER / EER rating where applicable
  • Ventilation system type, SFP, and heat recovery efficiency
  • Hot water system type and fuel
  • Building energy management system (BEMS) details if specified
Lighting & renewables
  • Lighting design — luminaire type, circuit power (W/m²), and controls strategy
  • Daylighting provisions and automatic dimming controls
  • Presence detection and occupancy sensor zones
  • Solar PV system size and array orientation (if included)
  • Solar thermal, wind turbines, or other renewable technologies

Getting more from your SBEM assessment.

Most commercial buildings we assess contain at least one opportunity to improve the EPC rating — often without significant additional build cost. Because SBEM models the building at component level, it reveals which elements have the most influence on the overall Building Emission Rate.

Early engagement lets us identify these opportunities while design decisions are still open. Lighting specification, glazing G-values, and HVAC controls strategy are the three areas where modest changes most frequently produce meaningful EPC improvements without affecting the building's visual or operational character.

A better commercial EPC has direct commercial value — higher-rated buildings command better rents, attract institutional investors with ESG commitments, and face lower risk of stranded asset status as Minimum Energy Efficiency Standards tighten.

Fabric first
Higher-performance insulation, better glazing U-values, and reduced thermal bridging reduce space heating demand — the largest single energy use in most commercial buildings outside of air conditioning.
Lighting specification
LED lighting with occupancy sensors and daylight-linked dimming is one of the most cost-effective ways to improve SBEM results. Circuit power (W/m²) and controls strategy both directly input into the model.
Efficient HVAC & renewables
High-SCOP heat pumps, heat recovery ventilation, and solar PV can each deliver meaningful BER improvements. We model the interaction between systems to identify the most cost-effective combination for your project.
Glazing G-values
Solar control glazing (low G-value) reduces cooling loads in south- and west-facing facades. This is often under-specified at design stage and has a disproportionate impact on SBEM results for glazing-heavy buildings.

"Build Envelope's guidance and expertise helped us quickly navigate the assessment process and achieve a hassle-free, cost-effective SBEM Assessment, BRUKL Report and EPC for our latest office development."

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Office Development
Level 4 & 5 NDEA — all building types covered
Our dual-level NDEA accreditation through Elmhurst Energy means we can assess everything from simple single-zone offices to complex mixed-use schemes with district heating and specialist HVAC.
5-day turnaround on design stage reports
Most design stage BRUKL reports are returned within 5 working days of receiving complete information. We confirm turnaround time at the point of instruction so you can plan your programme accordingly.
SAP and SBEM under one roof
For mixed-use developments requiring both domestic and non-domestic assessments, we handle both — avoiding the programme coordination issues that arise when SBEM and SAP are managed by separate contractors.

Local NDEA-accredited assessors for commercial buildings across the Midlands and South West.

We understand commercial building control requirements across our core service areas. Our Level 4 and Level 5 assessors handle offices, retail, education, healthcare, and mixed-use developments.

Birmingham & West Midlands

SBEM calculations and commercial EPCs for offices, retail units, and mixed-use developments across Birmingham, Solihull, Coventry, Wolverhampton, and the wider West Midlands. BRUKL reports for Building Control submission.

Bristol & South West

Commercial energy assessments across Bristol, Bath, South Gloucestershire, and the surrounding South West. We navigate local authority sustainability policies for planning compliance alongside Part L.

Worcestershire

Based in Worcester — SBEM calculations across Malvern, Droitwich, Evesham, Bromsgrove, and Redditch. Our home county with the fastest turnaround and strongest local relationships.

Gloucestershire

Commercial Part L compliance for developments across Cheltenham, Gloucester, Stroud, Tewkesbury, and the Cotswolds. Offices, retail, education, and healthcare buildings assessed.

Oxfordshire

SBEM assessments for non-domestic buildings across Oxford, Banbury, Bicester, Witney, and the wider Oxfordshire area. Design stage and as-built calculations with BRUKL output.

Wider England & Wales

As NDEA-accredited assessors, our SBEM calculations and commercial EPCs are valid across the whole of England and Wales. We regularly assess buildings outside our core regions — contact us wherever your project is.

Looking for SBEM calculations near you? Whether you have a commercial office in Birmingham, a retail development in Bristol, or a mixed-use scheme in Oxfordshire — our accredited assessors deliver Part L compliant SBEM reports with practical optimisation advice. Call 01386 365145 or email us to get started.

Common questions about SBEM calculations.

BRUKL stands for Building Regulations UK Part L. It is the formal report output from an SBEM assessment that demonstrates a non-domestic building's compliance with Part L of the Building Regulations. It is required by Building Control at both design stage (before construction) and as-built stage (after construction).

The BRUKL Report includes the Building Emission Rate (BER), Target Emission Rate (TER), and confirmation that the building meets or exceeds the required standard. Without it, Building Control cannot sign off the project and a commercial EPC cannot be produced.

SBEM is used for non-domestic buildings — offices, retail, education, healthcare, and industrial. SAP is used for domestic buildings — houses, flats, and residential conversions. They are different assessment methodologies and different software tools, but both ultimately produce an EPC.

For mixed-use developments with both residential and commercial elements, both SBEM and SAP assessments are required. We are accredited for both and can handle mixed-use schemes as a single commission.

NDEA Level 3 covers simpler, smaller non-domestic buildings — typically smaller single-zone buildings with simple HVAC. Level 4 covers most standard commercial, education, and healthcare buildings. Level 5 is required for complex buildings with district heating, CHP, or other specialist energy systems.

Our dual Level 4 and Level 5 accreditation means we can assess all standard building types without restriction. We confirm the required level at the point of enquiry.

Yes. SBEM assessments are required not only for new builds but also for significant extensions to existing non-domestic buildings (typically over 100m² or greater than 25% of existing floor area) and for major refurbishments — particularly where the building fabric, HVAC systems, or energy envelope is significantly changed.

A change of use from one building classification to another (e.g., retail to office) can also trigger the requirement for a new SBEM assessment. If you are unsure whether your project requires SBEM, contact us and we will advise based on the specific works proposed.

The earlier the better. Engaging an SBEM assessor at RIBA Stage 2 or early Stage 3 — when the building form, orientation, and HVAC strategy are being determined — allows energy performance to be built into the design rather than retrofitted. This is also when specification changes are least costly to make.

Late engagement, when drawings are finalised and specifications are locked, significantly limits what can be done if the initial assessment result is below target. It can also result in programme delays if the design needs to be revised to achieve compliance before the Building Control submission.

Yes — the SBEM assessment produces both the BRUKL Report (for Building Control) and the commercial EPC. The EPC rating is based on the SBEM results, expressed as a letter from A (most efficient) to G.

The commercial EPC rating has real commercial implications. The Minimum Energy Efficiency Standards (MEES) currently require commercial properties to have a minimum EPC rating of E before being let. The government has indicated plans to tighten this to C by 2027 and B by 2030. Buildings assessed now that achieve C or above will be better positioned for future lettability and investment value.

5-day turnaround

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