What Is NABERS? A Complete Guide to Building Ratings

NABERS is the National Australian Built Environment Rating System, a government-backed scheme for measuring the environmental performance of Australian buildings. Its operational ratings cover energy, water, waste and indoor environment. Energy and water ratings use measured consumption over a 12-month period, while other tools have their own evidence requirements.

NABERS has operated since 1999 and is administered by the NSW Government on behalf of Australian governments. Accredited assessors prepare rating applications, which NABERS checks and certifies. Operational ratings are generally valid for 12 months. NABERS certification and quality assurance

This guide covers what NABERS measures, how the star scale works, what can be rated, how a rating is calculated, how it differs from Green Star and NGER, who needs one, and what's changing across 2025 and 2026.

What Is NABERS?

NABERS compares measured building performance with the relevant sector benchmark. Each tool defines its own rating scope, evidence requirements and adjustments.

For an operational NABERS Energy rating, design specifications alone aren't enough. The assessment uses actual consumption and the applicable rating rules. An accredited assessor checks the evidence and submits the rating to NABERS for certification.

Certified ratings can support leasing, procurement and investment decisions. NABERS maintains a ratings register, and the Commercial Building Disclosure program imposes specific disclosure requirements on affected office transactions.

What Does NABERS Measure?

NABERS is a family of ratings, not a single score. Most people mean NABERS Energy when they say NABERS, but four operational ratings sit under the same framework, with a fifth covering construction.

NABERS Energy. Measures greenhouse gas emissions from the energy a building consumes, adjusted for size, climate zone, hours of operation, and occupant density. This is the rating referenced in leases, government policy, and mandatory disclosure. It covers every energy source the building draws on, including electricity, gas, and diesel.

NABERS Water. Measures mains water consumption against comparable buildings, accounting for recycled and captured water. Widely used across offices, shopping centres, and hotels where water is a material operating cost.

NABERS Waste. Measures how much of a building's waste is diverted from landfill and how well the waste stream is managed. It relies on waste contractor data rather than meter data, which makes the collection problem different but no less fiddly.

NABERS Indoor Environment. Measures the quality of the space people actually occupy, covering air quality, thermal comfort, lighting, and acoustics, assessed through physical measurement and occupant surveys.

NABERS Embodied Carbon. This tool assesses upfront emissions from building materials and construction. Its calculation resources are updated separately from operational energy ratings, so assessors need to use the applicable rules and emissions-factor database.

There's also the Renewable Energy Indicator, which isn't a rating in its own right. It appears on every NABERS Energy certificate and shows how much of the building's energy came from renewable sources, including on-site generation, voluntary purchases, and the renewable share already in the grid.

How Does the NABERS Star Scale Work?

NABERS star ratings provide a benchmark against comparable buildings. The familiar descriptions on the scale are:

1 star Considerable room for improvement
2 stars Below the market average
3 stars Around the market average
4 stars Good performance, ahead of the market
5 stars Excellent performance
6 stars Market-leading performance

Ratings need to be renewed, and changes to benchmarks or emissions factors can affect the result even when consumption is unchanged. The effect depends on the building, rating tool and applicable methodology. Check the current rules rather than assuming a fixed number of stars will be retained.

What Can Be Rated: Base Building, Tenancy, or Whole Building?

For offices, NABERS Energy offers base building, tenancy and whole-building rating scopes. Data centres use different scopes, including IT equipment, infrastructure and whole facility. NABERS data-centre rating scopes

Base building. Central services controlled by the owner, including HVAC, lifts, common area lighting, and car park ventilation. This is the rating most often required for mandatory disclosure, and the one landlords are judged on.

Tenancy. Energy consumed inside a tenant's own space, covering their lighting, equipment, and supplementary services. This is the rating an occupier controls and the one their own reporting usually depends on.

Whole building. Base building plus every tenancy combined. It's the honest total, and it's the practical option where sub-metering doesn't cleanly separate landlord and tenant loads.

Coverage extends well past offices. NABERS rates shopping centres, hotels, data centres, hospitals, apartment buildings, warehouses and cold stores, retirement living, aged care, schools, and retail stores. Each sector has its own tool and its own benchmark set, which is why a 4-star hotel and a 4-star office aren't measuring the same thing.

How Is a NABERS Rating Calculated?

An office energy assessment combines 12 months of consumption data with the building parameters required by the relevant rules. These can include area, operating hours and other normalising factors. The accredited assessor checks the information and submits the assessment to NABERS for certification.

Normalisation makes comparisons more useful by accounting for specified characteristics of the building and its use. The adjustments vary by sector and rating scope, so confirm the required inputs with the assessor before assembling a portfolio dataset.

Assessors need reliable evidence for the rating period. Missing reads, estimated bills or misallocated meters can complicate the assessment. Errors discovered after year-end should be discussed with the assessor and corrected through the applicable process. Closing the reporting year doesn't make a data error impossible to fix.

New buildings and major refurbishments can't wait a year to say anything. They use a Commitment Agreement instead, a contract to design, build, and commission the building to a target rating, with the performance rating confirmed once the building has run long enough to produce a full 12 months of data. For the step-by-step assessment process and how to lift an existing rating, see our guide to NABERS energy ratings for property managers.

How Is NABERS Different From Green Star, NatHERS, and NGER?

These get used interchangeably and they measure different things at different points in a building's life.

NABERS vs Green Star. Green Star covers a wider range of sustainability criteria through tools for buildings, fitouts, communities and operations. Green Star Performance also assesses existing buildings, so Green Star isn't limited to design and construction. NABERS provides more focused performance measures, and the two schemes can be used together. Green Star rating tools

NABERS vs NatHERS. NatHERS assesses the energy performance of homes using modelling. NABERS operational ratings focus on measured performance in the sectors and spaces covered by its tools, including apartment-building common areas.

NABERS vs NGER. NGER is a mandatory corporate reporting obligation administered by the Clean Energy Regulator. It asks for absolute energy and emissions across a controlling corporation's whole operations against threshold tests. NABERS is a building-level efficiency benchmark, usually voluntary, that normalises consumption to make buildings comparable. Same underlying meter data, different question. Our guide to automating NGER reporting covers the corporate side.

NABERS vs climate disclosure. Under the Australian Sustainability Reporting Standards, in-scope entities report climate risk and emissions at the entity level. NABERS doesn't satisfy that obligation, but the electricity data behind a NABERS Energy rating is the same data feeding Scope 2 emissions calculations. Buildings that already run clean NABERS data usually find disclosure season far less painful.

Who Needs a NABERS Rating?

Office space being sold or leased. The Commercial Building Disclosure program requires a Building Energy Efficiency Certificate, including a current NABERS Energy rating, in most cases where office space of 1,000 square metres or more is offered for sale, lease, or sublease. Civil penalties apply for non-compliance.

Buildings chasing Commonwealth tenants. Since 1 July 2025, the Net Zero in Government Operations Strategy sets a 5.5-star NABERS Energy requirement for new office leases of at least four years and at least 1,000 square metres of net lettable area, subject to its scope and exceptions. It distinguishes base-building and tenancy requirements and provides a non-metropolitan exception. From 1 July 2026, its all-electric requirement applies to new building purchases and construction contracts, where available, excluding backup generation. It is not a blanket rule that every new office lease must be all-electric. Commonwealth strategy, pages 7–8

State government policy. The NSW Government Resource Efficiency Policy sets its own minimum NABERS Energy requirements for government tenancies and government-owned data centres, and other jurisdictions apply similar procurement rules.

Everyone else, voluntarily. Most NABERS ratings aren't legally required. Owners rate hotels, shopping centres, warehouses, and apartment buildings because tenants, lenders, and investors ask for the number, and because a rating gives an asset manager a defensible way to compare buildings across a portfolio.

What's Changing for NABERS in 2026?

GreenPower reporting has changed. NABERS retired the separate Energy with GreenPower result in July 2025. The Renewable Energy Indicator reports renewable energy use separately. Check the current certificate and methodology when comparing ratings across this change. Renewable Energy Indicator

Emissions factors affect the result. Grid decarbonisation changes how energy use translates into emissions. The rating effect of gas use depends on the building and the applicable benchmark. Use NABERS' current guidance and prediction tools rather than assuming every gas-reliant building loses half a star. NABERS benchmark guidance

Plan capital works using current guidance. Before relying on a future benchmark change in an electrification business case, check the latest NABERS consultation outcomes and test the building's own consumption. Proposed changes should not be presented as settled rating rules.

Embodied-carbon resources have been updated. NABERS published National Emission Factors Database version 2026.2 on 29 July 2026. Projects using the embodied-carbon tool should check which database and rules apply to their assessment. Current emissions-factor database

Disclosure reform needs to be tracked. A proposed expansion of Commercial Building Disclosure should be distinguished from obligations already in force. Check the program's current coverage, exemptions and commencement dates before telling an owner that a rating is mandatory. Commercial Building Disclosure

How Utilified Keeps NABERS Data Rating-Ready

For energy ratings, assembling a complete year of consumption evidence is often a substantial part of the preparation. Utilified's UMS helps organise utility records across a portfolio. The accredited assessor remains responsible for applying the rating rules.

A unified utility record. UMS brings invoice and meter information together against sites and connections, helping teams retrieve the records relevant to a building and rating period.

Invoice validation. Joule Invoice Reading extracts invoice information, and UMS supports checks against recorded contracts and tariffs. Reviewing discrepancies throughout the year can reduce the cleanup required when an assessor requests the evidence.

Visibility between ratings. Interval data can help teams investigate after-hours consumption and changes in demand. The findings still need to be interpreted in the context of the building's operation.

Reusable evidence. Well-organised consumption records can support several reporting workflows. NABERS, NGER and climate disclosure each have their own boundaries, calculations and assurance requirements, so the same dataset still needs to be assessed for each purpose.

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Frequently Asked Questions

What does NABERS stand for?

NABERS stands for the National Australian Built Environment Rating System. It rates the measured environmental performance of buildings and tenancies from zero to six stars across energy, water, waste, and indoor environment quality.

Is a NABERS rating mandatory?

NABERS is mandatory in specified circumstances. Commercial Building Disclosure generally applies to affected office space of at least 1,000 square metres offered for sale, lease or sublease, subject to exemptions. Government procurement and lease requirements have their own scope. Check the applicable rules for the building and transaction.

How long does a NABERS rating last?

Generally 12 months from the date it's issued. Buildings that transact or lease regularly need a continuous data pipeline, because a lapsed rating can stop a building being advertised for sale or lease.

What is a good NABERS Energy rating?

The star scale describes 4 stars as good and 5 stars as excellent performance. A procurement requirement may set a higher minimum, with conditions about the building, lease duration and rating scope. Compare like-for-like ratings and the current benchmark.

Can a new building get a NABERS rating before it has a year of data?

A new building can enter a NABERS Commitment Agreement to target an operational energy rating. That target is distinct from the certified performance rating obtained once the required operating data is available.

Does NABERS cover anything other than offices?

Yes. Shopping centres, hotels, data centres, hospitals, apartment buildings, warehouses and cold stores, retirement living, aged care, schools, and retail stores all have NABERS tools, each with its own benchmarks.