Co-evolution: How NABERS and the market move together

To stand the test of time, NABERS hasn’t stood still.

What became NABERS Energy began with offices. Over time both the rating and its role in the market have expanded.

In 1999, what we now know as NABERS helped answer one question: How efficient is this office building?

Today, NABERS answers many questions. Building owners ask: Where should I invest? Tenants ask: Which building is aligned with our climate commitments? For investors, the question is: Which portfolio performs better? For regulators: Is this policy working? And for banks: Which assets are lower risk?

The questions have multiplied as the market has matured. At every stage, NABERS has evolved alongside the market it measures.

Image: Office Building: 60 King William, Adelaide (Charter Hall)

“NABERS Energy for offices has endured because it has evolved. The algorithms, methodology and benchmarks have been repeatedly reviewed and refined, responding to changes to technology, policy, industry practice and the electricity system.”

Magali Wardle , Head of Market Development, NABERS, 2026

The evolution of NABERS Energy can be traced through a handful of turning points.

The Australian Building Greenhouse Rating, the precursor to NABERS Energy, launched for offices in 1999.

From 2000, benchmarks and algorithms were updated each year as datasets expanded.

In 2011, a sixth star was added when market leaders outgrew the original scale.

In 2016, Co-Assess launched, making it easier to rate office base buildings and tenancies together.

From 2021, emissions factors were updated annually as Australia’s electricity grid decarbonised.

In 2023, the Renewable Energy Indicator began distinguishing energy efficiency from renewable energy procurement.

And another major update is now signposted for 2030, when the star rating will focus on energy efficiency while the Renewable Energy Indicator recognises low-emissions energy sources.

With each change, NABERS has moved with market while maintaining the consistency that makes more than 25 years of performance comparable.

Measuring performance

Before NABERS, energy performance was typically expressed through technical metrics, such as kilograms of carbon dioxide per square metre per year. Useful for specialists, but hardly the language of boards, investment committees or leasing agents.

NABERS distilled technical complexity into a simple star scale.

By creating a common language, NABERS transformed operational performance into something everyone in Australia’s office market could understand and, eventually, compare.

An accredited assessor network, rigorous audits and transparent rating rules gave the market confidence that a 4.5 star rating in Perth meant the same thing as a 4.5 star rating in Melbourne.

That confidence helped turn a technical rating into a trusted market benchmark.

“Aiming for 4.5 stars is a much easier concept to communicate than aiming for a normalised energy intensity of 80 kgCO₂e per m² per annum. Everyone from the CEO down could talk the star scale, with more stars meaning better performance.”

Bruce Precious , "Energy Efficiency in Commercial Buildings, 2022

Comparing performance

When the NABERS Energy for office buildings rating was designed in 1999, 2.5 stars represented average performance, 4 stars signified market leadership, and anything above 4.5 stars was considered largely theoretical.

“There was no expectation in 1999 that such radical improvements were possible, let alone able to be achieved across the entire office sector.”

Dr Paul Bannister, NABERS Nearly 25 Years On, 2024

By 2008, the year NABERS expanded nationally, 1999’s theoretical achievement was reality. That year, 58 office buildings were awarded 5 star NABERS Energy ratings.

However, NABERS ratings were far from ubiquitous. Australian Government procurement guidelines accelerated market adoption, setting minimum 4.5 NABERS Energy expectations for Commonwealth office leases, but the real watershed came in 2010 with the Commercial Building Disclosure (CBD) Program. For the first time, buyers and tenants could compare operational performance of office buildings before signing a lease or making an investment decision.

Collaborating to improve performance

Energy performance doesn’t stop at the tenancy door.

Tenancy ratings, available from AGBR’s inception, recognised that owners and occupiers controlled different parts of a building’s energy use. In 2008, the CitySwitch Green Office program in New South Wales went national, encouraging corporate tenants to improve their NABERS Energy ratings by two stars.

As attention expanded from base buildings to the energy performance of occupiers, NABERS introduced Co-Assess in 2016, making it easier to rate tenancies alongside the base or whole building. Its uptake has grown steadily. By FY26, 15% of Office Energy ratings were lodged through Co-Assess.

Not only that but the data shows that office tenancies are showing the same trend as base buildings where regular measurement leads to better energy efficiency and higher NABERS star ratings.

NABERS certified ratings for office tenancies by energy intensity and average star rating, FY16 to FY26

Note: This chart shows how regular measurement of tenancy energy efficiency led to better management and improved performance over time. Source: NABERS, 2026.

Valuing performance

Elevating performance

Behind the scenes, the NABERS team has always been hard at work to refine the benchmarks, improve the accuracy of ratings, and build the ecosystem to support the industry.

The NABERS Commitment Agreement, launched in 2001, has fundamentally changed how buildings are designed and delivered. The Green Building Council of Australia’s report, Closing the performance gap in Australia’s commercial office sector, found a NABERS Commitment Agreement is a critical factor in translating design intent into buildings that perform.

By 2011, enough buildings had reached the upper limits of the original five-star scale, and NABERS introduced a sixth star. This created new headroom for leadership rather than allowing excellence to plateau. That year, just three office buildings achieved the new 6-star benchmark. By FY26, that number had grown to 171.

“As a company with a strong commitment to leading the market in energy efficiency and sustainability, we welcome the extension of the NABERS rating scale. It provides the opportunity for us to set higher targets, and to demonstrate the effectiveness of our environmental initiatives across the portfolio.”

Michael Cameron, former CEO, GPT Group, 2011

Growth in 6-star NABERS Energy ratings from FY11 to FY26

Source: NABERS, 2026.

“We are lucky to have programs like NABERS because it takes us further and faster together.”

Davina Rooney, CEO, Green Building Council of Australia, 2025

Redefining performance

The story of NABERS Energy for office buildings is more than a sequence of methodology updates, new benchmarks and additional tools. It is a story of a market and a rating system growing together.

As investors sought consistent portfolio-level performance data, NABERS launched the Sustainable Portfolio Index in 2019. By 2026, it captured 8.2 million sqm of office floor space.

As Australia’s electricity grid decarbonised, NABERS introduced the Renewable Energy Indicator in 2023, distinguishing renewable energy sourcing from energy efficiency.

As NABERS Energy became more deeply embedded in finance, procurement and policy, NABERS responded with a Policy Toolkit for governments, contributed to the development of the Australian Sustainable Finance Taxonomy and supported the expansion of the CBD Program, with large office tenancies among the first proposed additions.

The next major change comes in 2030.

As the grid decarbonises, low emissions will no longer necessarily mean low energy use. From July 2030, the NABERS Energy star rating will focus on energy efficiency, while the Renewable Energy Indicator will recognise low-emissions energy sources.

NABERS is also looking further ahead. Work on energy flexibility is exploring how future ratings could recognise buildings that shift, store and share electricity as they become more active participants in the grid.

The market has changed what it asks of NABERS. And NABERS, in turn, has changed what the market measures and values. That is co-evolution.

Want the full story?

For a deeper dive into the milestones, people, projects and policy decisions that shaped NABERS, download NABERS: 25 Years of Game Changers. It's a rich history of how a simple idea became one of Australia’s most influential building performance programs.

Or read the Global Guide: Energy Efficiency in Commercial Buildings, written by Bruce Precious and published in 2022.

Timeline: NABERS Energy for offices

Year	Milestone	Why it matters
1999	Australian Building Greenhouse Rating (ABGR) launched	Following a 1998 pilot, operational performance becomes measurable, with whole-building, base-building and tenancy ratings comparing offices on actual energy use.
2000 onwards	Benchmarks and algorithm refined annually	Ratings become more accurate as larger datasets improve benchmarking across climates and building types.
2001	NABERS Commitment Agreements introduced	Developers commit to verified operational outcomes during design, helping close the gap between design intent and real-world performance.
2007	Government leasing requirements introduced	Performance becomes a procurement issue as the Australian Government adopts minimum 4.5 Star NABERS Energy ratings for office leases.
2008	NABERS rolled out nationally	Performance becomes nationally consistent as ABGR expands into a single Australian rating system.
2010	Commercial Building Disclosure (CBD) Program begins	Performance is made public as mandatory disclosure for offices over 2,000 m² transforms NABERS into valuable market information.
2011	Property Council of Australia/IPD Green Property Investment Index launched	The first Index finds that higher-rated NABERS buildings outperforms lower-rated buildings by around 3%.
2011	6 star NABERS Energy introduced	Leadership is redefined as a sixth star gives pace setters a new target to pursue and a trajectory to net zero.
2016	Co-Assess for Office Energy launched	For the first time, NABERS Co-Assess allows base buildings and tenancies to be rated together, with each receiving their own certified NABERS Energy rating.
2017	CBD Program threshold lowered	Transparency expands as the mandatory disclosure threshold is lowered to 1,000 m².
2018	First Co-Assess office tenancy rating.	Brisbane’s 66 Eagle Street achieved the first Co-Assess rating across six tenancies.
2019	Sustainable Portfolio Index (SPI) launched	Performance scales up from individual buildings to entire investment portfolios.
2020	Future of NABERS Energy project commences	The next evolution begins as NABERS prepares for a changing energy system, including electrification and the Greenhouse Gas Protocol’s shift to market-based accounting.
2021 onwards	Annual National Greenhouse Accounts updates occur	Methodology evolves continuously alongside Australia's decarbonising electricity grid.
2022	Global Guide: Energy Efficiency in Commercial Buildings published	This guide outlines the key success factors of NABERS Energy ratings in Australia.
2023	Net Zero in Government Operations Strategy released	Australian Government policy embeds minimum NABERS standards across Commonwealth leasing, refurbishment and new construction.
2023	Renewable Energy Indicator (REI) launched	NABERS expands its Energy rating to recognise renewable energy procurement alongside energy efficiency.
2024	NABERS Policy Toolkit released	Guidance helps governments and large organisations embed NABERS consistently into procurement, leasing and policy.
2024	High performance becomes mainstream	CBRE finds 44% of pre-2000 office buildings have 5-star NABERS Energy ratings or above.
2025	NABERS Energy with GreenPower retired	NABERS methodology is refined to reflect the maturity of Australia’s renewable electricity market.
2025	Australian Sustainable Finance Taxonomy launched	Operational performance enters the language of finance, with 5.5 star NABERS Energy recognised as a key proxy.
2025	More market evidence emerges	JLL finds high NABERS-rated offices deliver 7% higher rents, 5.1% lower vacancy and 45 basis points lower yields.
2026	Energy Flexibility Feasibility Study published	NABERS begins exploring how to reward buildings that shift, store and share electricity.
2030	Office Energy methodology updates	Performance is redefined again for a decarbonised electricity grid.