SBEM calculations

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Calculating SBEM

SBEM is short for ‘Simplified Building Energy Model’ — a government scheme for deriving energy rating. The best way to remember it, is that SBEM figures form the commercial counterpart of SAP figures.

SBEM reports:

  • Ensure that the Building Emission Rate (BER) isn’t greater than the Target Emission Rate (TER).
  • Assess the fabric of the building
  • Assess for energy efficiency, all ventilation, heating, cooling, water heating and permanent lighting systems.
  • Set down control measures designed to reduce solar gains in summer, thereby reducing the need to install air conditioning.
  • Ensure that steps have been taken to allow the building to function energy efficiently.

There are two formats for SBEM calculations: One covers new builds (L2A); the other deals with conversion and extension work (L2B). The most important purpose of SBEM figures is to create a BRUKL (Building Regulations Part L) report which generates a brand new EPC, or one that has recently been updated.

What do SBEM calculations do for me?

SBEM calculations are mandatory under Part L (England & Wales), Section 6 (Scotland), Part F1 (Northern Ireland) of Building Regulations. These are all documents relating to power & fuel conservation. SBEM calculations were introduced with the 2006 UK Building Regulations.

SBEM calculations are a prerequisite for any new or updated Energy Performance Certificate (EPC), and give a property rating ranging from one, to one hundred — the higher the number, the higher the efficiency. It is illegal to sell or rent out a commercial building that has no EPC.

What information goes into an SBEM?

For us to make SBEM calculations, our customer needs to provide the following information. The list is not exhaus-tive but it’ll give you a fair idea of what we need:

  • Floor plans
  • Elevations
  • Sections
  • Site Plans
  • Insulation type and thickness
  • U-values for all openings
  • Heating system specifications
  • Details of the method used to produce hot water
  • Lighting specifications (including lighting controls)
  • Cooling and ventilation specifications
  • Details of any renewable technologies
  • Accredited building details

It’s important not to over-simplify SBEM calculations, however. Final figures are dependent on the nature of the construction: new build, conversion or extension. In all cases two reports are generated — new builds require ‘design stage’ and ‘as built’. reports. Conversions and extensions are governed by L2B SBEM Calculations and give rise to a ‘notional’ and a ‘proposed’ report.

L2A SBEM New-Build Calculations

Design Stage


  • Scrutinise and pass the property’s construction details before construction starts.
  • Use specialist SBEM software to generate a TER rate and show BER compliance.
  • Then create an assessment of predicted energy use.

As Built Report

  • On completion of the project, details of the construction are assessed afresh and final calculations added, e.g. the designated type of boiler model.
  • The EPC derives from this report.

The Calculation of L2B SBEM (extensions and conversions)

Notional Report


  • Carry out an assessment of the construction of the whole property, in addition to the proposed extension or conversion.
  • Create a benchmarked data report
  • Use specialist SBEM software to generate a TER rate and to prove that the building is complies with BER regulations.

Proposed Report


  • Use benchmark data for existing components. Actual performance data are used for new or upgraded components.
  • Use specialist SBEM software to generate a TER rate and to prove that the building is complies with BER regulations.
  • Pass the property only when its performance values are lower than benchmarked standards.
  • Also check that overall BER measurements are lower in the proposed report than in the notional report.
  • We will replace the existing EPC with a new EPC, where SBEM calculations demonstrate that all building performance values are lower in the proposed report than in the notional report.

Scheduling SBEM Calculations

Two SBEM assessments are required: one at the beginning of the building project, and another at the end. We can produce SBEM calculations at Design and As-Built Stages.

Design Stage SBEM Calculations

Design Stage SBEM Calculations must be produced before building work starts, so you should submit an SBEM report and Building Control/ Warrant Application to a Building Control Body or Verifier (Scotland), without delay, or building work cannot start.

As-Built Stage SBEM Calculation

On completion, As-Built SBEM Calculations are needed to ensure that the finished building remains compliant.

What exactly does an SBEM Calculation offer?

SBEM calculations indicate the carbon footprint of the surveyed building as required under Building Regulations Part L. These calculations demonstrate energy costs and carbon emissions resulting from the proposed design.

Changes are often made as the project progresses, in consultation with architects, developers or customers to make sure that the building is always in full compliance with current regulations. We recommend that you engage an official accredited consultant before committing to your final design.

Do I also need an EPC?

The short answer is, yes. Post construction — once all works have been completed according to SBEM specifications — an Energy Performance Certificate (EPC) is created using SBEM figures. If you have engaged us to carry your SBEM calculations we will supply your EPC free of charge.

You can rely on us for exceptional service

  • We can carry out SBEM calculations for projects of any size.
  • We will review all specifications and plans
  • We will offer recommendations, and make sure we meet your deadlines.
  • We will supply your Energy Performance Certificates (EPCs) free of charge.
  • Our staff are all accredited experts, highly experienced in their field
  • We can offer cost-effective neutral advice on how to increase the energy efficiency of your property.
  • We take pride in having a fully trained team of professionals, dedicated to helping you meet your deadlines. We will keep you up to speed throughout the process. If it suits you we are always willing to engage directly with your Building Control Office or Design Team.
  • Our assessors are CIBSE qualified to Level 5. This means we are qualified to carry out SBEMs on the most com-plex projects — those which incorporate, for example, atriums and complicated ventilation systems.

How much time should I allow?

Of course, it depends on the size and duration of your project. But as a rule of thumb Briary Energy sets itself a target for report completion within 5 to 10 working days following application.

The consequences of failure

Simple. It is illegal to sell or rent any commercial property that does not have a compliant EPC. Your building must pass its SBEM. You can see how important it is to carry out SBEM calculations before starting to build — if the build-ing does not reach building regulation standards, we can offer advice to improve the situation. Clearly remedial work becomes more and more difficult, not to mention more expensive as the project progresses.

Briary Energy offers wide-ranging support and guidance from start to finish of the whole SBEM process. Some of our competitors simply carry out calculations. Briary Energy offers our customers consultancy services to ensure you have all the data and information needed for an SBEM pass.

Dynamic Simulation Modelling

DSM software is designed to calculate data for new build commercial properties. It is also highly accurate and takes account of other external factors capable of impacting on energy consumption.

DSM software comes into play with large scale complex constructions such as airports, shopping centres, or sky-scrapers. But the software can prove very useful for those customers who want a more detailed analysis for their intended non-domestic project.

In commercial buildings we use Dynamic Simulation Modelling (DSM) to provide a much more detailed and accurate assessment using a 3D model of your building. This model enables us to analyse:

  • Thermal Performance / Construction
  • Renewables and Technologies
  • Energy usage
  • CO2 Emissions
  • Overheating
  • Daylight / Sunlight Assessment
  • Ventilation / Airflow
  • Occupant Comfort
  • BREEAM / LEED Performance

Briary Energy typically use DSM for large developments such as hotels and office blocks.

Why Briary?

  • Use of latest technology to model and test your building
  • Fast and effective service
  • Experienced Assessors ensure a pass without compromising or changing your design
  • Ability to package up SAP and SBEM assessment tools with DSM to ensure a robust and compliant report
Briary Energy SAP Calculations

Contact us today to talk about your upcoming project – it could save you on average £800* per plot!