From promise to performance: The standards changing the way we deliver net zero buildings

BCO Conference 2026 insights: The journey to net zero carbon buildings is paved with acronyms. It can be confusing, overwhelming and off-putting.

In an ideal world, realising ambitions to protect the future of our planet would be as simple as possible. In reality, standardisation and regulation play a critical role in ensuring the long-term decarbonisation of the built environment. The trick is knowing how cut through the noise.

That’s where NABERS UK comes in. A rating system that is more straightforward than its abbreviation suggests, what does it measure and why does it matter?

The UK version of the National Australian Built Environment Rating System was officially launched in November 2020 and measures a building’s energy use in real time. That’s the USP. Where so many certifications and standards are assessed and evaluated largely based on design or specification, this one gauges the performance of an active, occupied building over a series of months. And you don’t get a much more accurate picture of a property’s energy use and output than that.

“NABERS doesn’t just give a snapshot of a building’s performance at the point of design”, explained Ellen Salazar, head of building services engineering at CIBSE. “It gives ongoing operational verification using 12 months of energy data.”

Recognised partnership

But how do we make NABERS and the new Net Zero Carbon Building Standard good friends?

Well, they already are, said David Partridge, chair of the UK NZCBS governance board.

NABERS results are audited and buildings are given a star rating. If a new building achieves a 5* rating or an existing building hits a 4.5* rating, it is automatically deemed to have satisfied the operational energy requirements of the new UK NZCBS.

One standard defines the ambition; the other indicates when and whether that ambition has been achieved.

The two standards are “joined at the hip”, said Partridge. And because a NABERS rating is independently verified over a 12-18-month period by accredited assessors, it’s a partnership that gives developers and owners a recognised, respected route to demonstrating operational net zero.

“It begins with an initial design review based on ambitions and assumptions,” said Salazar. “Then it goes into modelling, followed by a second assessment, handover and then those 12-18 months of operation monitoring, which ends in the actual performance rating.”

Vote of confidence

The commitment forces every decision, right from the early design stages, to be considered against the pursuit of a promised rating – a compelling vote of confidence for investors and occupiers alike.

And if a building doesn’t achieve its targeted NABERS rating immediately? Not a problem. In fact, this focus on the growth and evolution of a building is part and parcel of the process. Not designed as a pass-or-fail moment at practical completion, performance is expected to improve as occupation goes on and teams start to better understand a property and can more effectively fine-tune its operational performance. Data can be analysed, operational issues identified and improvements made.

“I think the net zero standard is a gift to offices,” said Partridge, referring to the fact that the industry has access to a certification that takes into consideration the complicated, ever-changing nature of an occupied building: properties where landlords control some systems and occupiers control the others; spaces where energy use shifts depending on how they are used; and where technology that promises the earth fails to live up to expectations in reality.

But what about embodied carbon? Not fixable with a BMS tweak or an adjustment of operating hours based on building use data over time, this is a much thornier issue to manage. The answer is not to make the targets easier, said Partridge, but to use them to highlight and tackle the materials and construction processes carrying the biggest carbon burden. A catalyst for innovation. Not a stick to be used to punish the industry, but an “on ramp” to help the sector collectively move in the right direction.

Words by Emily Wright