I recently had the pleasure of speaking with Michael Turner, a seasoned building energy assessor, to unravel the intricacies of the Simplified Building Energy Model (SBEM). As we sipped our coffee in his modest yet well-organised office, Michael’s enthusiasm for his field became palpable. He began by recounting his experiences in conducting SBEM assessments, and how these assessments play a pivotal role in the energy performance of non-domestic buildings in the UK.
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“To conduct an SBEM assessment,” Michael explained, “we start by entering the geometry of the building into our software. This includes the dimensions, layout, and materials used in the construction. It’s akin to creating a digital twin of the building.”
Zoning the Building
One of the critical steps in the SBEM process is zoning. Michael elaborated, “We zone the building into different ‘activities.’ Each zone represents a different use within the building, such as office spaces, storage areas, or retail sections. This zoning is crucial because different activities have different energy requirements. For instance, an office space will have different heating and lighting needs compared to a warehouse.”
This segmentation allows for a more precise calculation of energy consumption and carbon emissions. Michael emphasised, “By creating these zones, we’re able to assign specific energy usage patterns to each area, which makes our calculations more accurate.”
SBEM vs. SAP
Curious about how SBEM differs from SAP (Standard Assessment Procedure), I asked Michael to shed some light on the subject. “That’s a great question,” he said with a smile. “SAP is primarily used for domestic buildings, and it assesses the energy performance of homes. SBEM, on the other hand, is tailored for non-domestic buildings like offices, warehouses, and retail units.”
Michael explained that while SAP focuses on the overall energy performance of a home, SBEM delves deeper. “SBEM calculations consider not just the building as a whole, but also the different zones within it. This means we can make more detailed assessments based on the specific use of each area within a non-domestic building.”
The Design and As-Built Process
Michael walked me through the two main stages of SBEM assessments: the design phase and the as-built phase. “During the design phase, we evaluate the building’s energy efficiency to ensure it meets regulatory standards before construction begins. This is crucial for securing building permissions,” he said.
Once construction is complete, the as-built phase comes into play. “We verify that the completed building actually meets the energy performance standards set during the design phase. This is essential for obtaining completion reports and the Energy Performance Certificate (EPC),” Michael added.
Key Factors in SBEM Assessments
I was fascinated by the range of factors considered in an SBEM assessment. Michael listed them out: “We look at the construction type, U-values for walls, roofs, floors, and windows, as well as the efficiency of heating, hot water, and ventilation systems. These factors collectively give us a comprehensive picture of the building’s energy performance.”
He mentioned that the services within commercial and public buildings tend to be more complex and wide-ranging than in domestic applications. “This complexity means that the options within SBEM are much broader, allowing for a more detailed and tailored assessment.”
Tools of the Trade
Michael spoke about the various software tools used for SBEM assessments, including iSBEM, DesignBuilder, IES, and TAS. “These tools all use the underlying SBEM methodology, but they offer different capabilities. For instance, DesignBuilder, IES, and TAS allow for Dynamic Simulation Modelling (DSM) analysis, which includes full 3D modelling.”
This advanced modelling capability enables assessors to carry out more accurate and flexible assessments. “We can design out inefficiencies like overheating and design in desirable features like optimal daylighting levels and occupant comfort,” Michael noted.
The Importance of SBEM
As our conversation drew to a close, Michael reflected on the broader significance of SBEM. “SBEM is crucial for meeting the UK’s energy regulations. It helps us design buildings that comply with legal standards while promoting sustainability. By modelling energy use and pinpointing inefficiencies, we ensure buildings are energy-efficient and cost-effective.”
Michael’s passion for his work was evident. “This tool is key in reducing carbon emissions and supporting green construction practices. Its role extends beyond compliance; it drives the creation of buildings that are both environmentally responsible and economically beneficial.”
As I left Michael’s office, I had a newfound appreciation for the meticulous work that goes into SBEM assessments. These assessments not only ensure regulatory compliance but also contribute significantly to the sustainability and energy efficiency of our built environment.
John Williams
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