Maximising performance with NABERS UK ratings: observations from an assessor

NABERS UK Energy for Offices ratings are continuing to gain traction amongst investors, building owners and even occupiers, with material improvements in energy performance beginning to be measured, verified and certified. Owen Porter, licensed NABERS UK assessor, shares his experience of the rating scheme.

What is NABERS UK?

NABERS UK is a performance-based rating system for commercial buildings, currently focused on offices, that measures actual operational energy use over 12 months. It produces a 1-to-6 star rating reflecting how efficiently a building is operating, taking into account variables like occupancy, hours of operation, and climate.

The NABERS UK scheme, launched in November 2020, is based upon the Australian NABERS scheme which is widely recognised as the most robust of its kind as ratings are based on actual performance verified by measured energy use over a year, rather than modelled metrics like EPCs which do not reflect operational performance.

Verco’s Owen Porter, shares below his observations and experience of the scheme since becoming a licensed NABERS UK assessor last year.

The importance of delineated responsibilities

Through delineation of whole building energy use between landlords and each tenant, NABERS UK offers ratings to all the parties with responsibilities for energy performance in a multi-let office building. The landlord is rated on the base building performance which they have the agency to control and improve. Each tenant can be separately rated for their use of light and power in their demises, which are energy uses under their control. There is also a whole building rating available to assess a building’s overall performance. This would be most appropriate for buildings with a single occupier, but is also useful to show the aggregated performance of a whole multi-let building.

Landlords able to demonstrate a good base building rating can offer tenants proof that their building is well-managed and controlled, with reduced operating costs. Experience in Australia has shown that better ratings are associated with higher rents and lower void periods.

Tenants can promote to their staff that they are being provided with a better working environment as a result of good base building management and control, such as avoiding simultaneous heating and cooling. This promises comfort and wellbeing benefits and the likelihood of enhanced productivity, not to mention supporting corporate ESG and Net Zero goals.

Incentivising continuous improvement

NABERS UK ratings are not a one-off event: they are repeated each year. This continuous process is incentivising site teams to think seriously about driving performance improvement actions with the aim of increasing the rating year-on-year. The rating system in Australia has a proven track record of improving energy efficiency in buildings over time, and we are now beginning to see UK office buildings that have committed to the NABERS UK journey achieve improvements in their certified performance rating upon renewal.

The optimisation opportunity

Significant reductions in energy use do not have to come from major capital investment. Recent projects have shown how a building’s performance can be improved significantly by optimising the existing HVAC systems through fine-tuning of controls, closer management, and reacting quickly to faults. Combining NABERS UK with building optimisation programmes is proving to be a cost effective route to higher ratings, offering clear direction to site teams and ensuring savings made do not go backwards.

Documentation is key

Accurate, up-to-date documentation underpins every NABERS UK assessment. Keeping detailed records of energy use, building services and metering schematics, floor plans, and meter commissioning and validation certificates helps to significantly streamline the rating process. Compliant documentation is one of the biggest barriers facing building owners looking to begin their NABERS journey.

Verco can provide a NABERS UK Rateability Survey which is a recommended step ahead of formal certification to help ensure all required documentation is in place.

Transforming existing building stock is a journey

Many existing UK offices suffer from poorly-defined metering and controls strategies, and unclear operational responsibilities, often resulting in inconsistent performance and blurred accountability. NABERS UK is helping to bring much-needed structure and clarity to these areas. However, for older buildings, achieving this transformation will be a gradual process rather than an immediate fix.

In practice, the journey begins with incremental steps: establishing simple agreements to prevent conflict over plant operation, improving submetering to gain more detailed insights into energy end use, and clearly defining roles and responsibilities. These early measures help build stability and confidence, paving the way for more significant changes to leases, controls and operational and management practises. It is important to view these actions as part of a broader transformation - not as the end point.

Design for Performance (DfP) seeks to embed the right approach from day one in new developments, providing exemplars which demonstrate how aligning roles, responsibilities and technical systems from the outset can help deliver high performing buildings. For existing buildings, the challenge is to follow that lead by navigating today’s complexity and moving towards the clarity and accountability needed to drive lasting improvements in energy performance.

Into the future with NABERS UK ratings

Ambitious NABERS UK ratings are being considered as a recognised route to meeting the operational energy limits for offices under the UK Net Zero Carbon Buildings Standard (UKNZCBS).

In March 2021, the UK government consulted on a performance-based policy framework for large commercial and industrial buildings. The preferred option was to mandate disclosure of operational energy performance in offices via the NABERS UK scheme. The consultation received broad support from all key stakeholders, and the industry continues to advocate for its adoption, recognising its proven success in the Australian commercial buildings market. Indeed, “Over the past two decades, buildings rated with NABERS have saved almost $2 billion in energy bills and cut 13.4 million tonnes of carbon emissions”.

Find out more about the NABERS Sustainable Portfolios Index 2025

How Verco can help

A NABERS rating is based on clearly delineated requirements and provides a robust measure of relative building performance against peers. Engaging with NABERS leads to demonstrable year-on-year improvements in energy performance, while also boosting occupier productivity and wellbeing.

We can provide a rateability review so you know how ready your building is for NABERS.
We can provide NABERS assessments and help you understand what the findings mean.

Find out more about the Verco NABERS service