As part of the growing demand for NABERS rating in office buildings, whether they are new builds or retrofit. The demand for Design for Performance (DfP) and Energy for Offices is growing, Senior Consultant Owen Porter from Verco reflects on his achievements following the completion of multiple NABERS UK assessments, spanning base building and whole building Energy for Office ratings.
Can you tell me about your background and how you became a NABERS UK assessor?
Throughout my career as both an energy consultant and energy manager, I've consistently focused on optimising building performance, with extensive experience across the office sector. This background made pursuing NABERS UK Assessor certification a natural career move, especially given Verco's pioneering role in establishing the scheme and leading the UK's transition toward performance-based energy ratings. The opportunity to contribute to this shift from theoretical design ratings to actual operational performance aligns with my approach to energy management.
Can you walk me through the process of conducting a NABERS UK assessment?
Every NABERS UK assessment I conduct follows a systematic three-stage process. First, I do a comprehensive data review to determine if the building qualifies for rating. This means examining all the documentation - floor plans, building schematics, validation templates, lease agreements, and 12 months of energy data - to ensure everything is complete and accurate.
The second stage is the site visit, where I physically inspect the building to verify that what I see matches the documentation. I measure spaces, check equipment, record any differences, and gather specific details about how the building operates, and collect information for mu occupancy hours where required. Site visits almost always reveal something unexpected that requires follow-up research.
The final stage involves two parallel tasks: compiling a comprehensive evidence pack with all my documentation and site notes and completing the detailed NABERS UK calculator spreadsheet with the building's performance data. Once I'm confident the calculator is accurate and complete, I submit it to CIBSE Certification for their Level 1 audit. After addressing any questions from the audit and making any final modifications, the building receives its official NABERS UK rating certificate.
Can you tell me about your first NABERS UK Energy for Offices lodgement. What type of building was it, and how did you get involved?
My first NABERS UK assessment was for a single-tenant office building where we rated the whole building. I got involved because Verco had already conducted the initial rating the year before, and the client wanted to renew their certification. What made it particularly rewarding was seeing the building achieve a better rating than the previous year - it was a perfect example of how NABERS UK motivates building owners to improve their energy performance rather than just measure it.
What were the main challenges you encountered during that initial assessment, and how did you overcome them?
My first assessment was relatively simple, compared to larger multi-let base building assessments I have since completed, where the most significant challenges often relate to metering. Instead, the challenges were in ensuring the appropriate application of the rules to this building, such as determining whether a space constitutes as NIA, or whether a workstation can be classed as occupied during the Tenant Occupied Workstation Estimate (TOWE) survey.
How did you find working with the NABERS UK rules and technical guidance the first time around?
Although navigating the rules and technical guidance was a steep learning curve at first, the well-structured framework and detailed explanations made the process feel both methodical and robust. What really stands out is how comprehensive the rules are - almost every situation you encounter is specifically covered in the guidance documents. This level of detail makes the assessment process very methodical and gives me confidence that I'm applying consistent standards across all my ratings. It's rare to come across a scenario where you're left guessing about the correct approach.
What have you learned about building performance through conducting these assessments?
Conducting NABERS UK assessments has shown in practice the critical role of metering in understanding and steering building performance. Ultimately, success is measured at the meter.
Another key learning for me has been seeing the value of delineating responsibilities between the base building and tenant energy use. NABERS UK’s structure allows for this split, which not only clarifies accountability but also enables targeted improvements. For example, landlords can focus on central services and infrastructure, while tenants are encouraged to manage their own energy footprint from small power, lighting and comms.
What advice would you give to building owners or property managers looking to achieve a NABERS UK rating?
NABERS UK is really beginning to gain traction in the market. My advice to building owners pursuing formal NABERS UK certification is to consider conducting a rateability survey. This is essentially a pre-assessment of the building that can significantly streamline the rating process further down the line.
A rateability survey helps to identify gaps in the metering strategy, whilst also highlighting any missing or incomplete documentation, such as system schematics and maintenance records, which are essential for a successful assessment.
Such a survey can also provide insight into the building’s current potential rating, helping set realistic expectations and guide targeted improvements before formal submission.
Ready to take the next step in improving your building’s performance? Learn more about the NABERS Energy for Offices scheme today.