What Is NABERS?
NABERS (National Australian Built Environment Rating System) is the Australian government's initiative for measuring and comparing the environmental performance of existing buildings. It provides a star rating from 1 to 6 stars, where 1 star indicates poor performance and 6 stars represents market-leading performance. NABERS ratings are based on actual, measured performance data rather than design predictions, making them a trusted benchmark for building owners, tenants, and investors.
Originally developed for office buildings, NABERS now covers a wide range of building types including shopping centres, hotels, data centres, and apartment buildings. Through our referral service, we connect you with accredited NABERS assessors who can rate your building and help you understand where improvements can be made.
NABERS Rating Types
NABERS offers several rating categories, each measuring a different aspect of building performance:
- NABERS Energy: Measures the energy efficiency of a building based on 12 months of energy consumption data. This is the most common rating type and the one required under the Commercial Building Disclosure (CBD) program.
- NABERS Water: Rates water consumption efficiency, helping identify opportunities to reduce water usage through better fixtures, irrigation management, and cooling tower performance.
- NABERS Waste: Evaluates waste management practices including recycling rates, organic waste diversion, and total waste generation per person.
- NABERS Indoor Environment: Assesses indoor air quality, thermal comfort, lighting quality, and acoustic performance to determine occupant comfort levels.
Each rating type can be obtained independently. Many building owners start with a NABERS Energy rating and progressively add other categories as part of their sustainability strategy.
Commercial Building Disclosure Requirements
Under the Australian Government's Commercial Building Disclosure (CBD) program, most office spaces of 1,000 square metres or more must have a current NABERS Energy rating before they can be sold, leased, or subleased. A Building Energy Efficiency Certificate (BEEC) displaying the NABERS rating must be made available to prospective buyers or tenants.
Non-compliance with CBD requirements can result in penalties. Building owners should ensure their NABERS rating is current (ratings are valid for 12 months) and plan ahead, as the assessment process requires 12 months of utility data.
The 4.5-Star Minimum for Government Leases
The Australian Government has set a minimum 4.5-star NABERS Energy rating for all new government office leases. This policy applies to leases entered into by Commonwealth agencies and means that buildings seeking government tenants must achieve a high standard of energy performance. For building owners targeting government tenancies, investing in energy efficiency upgrades to reach 4.5 stars or above is essential.
Many state governments have adopted similar policies. An accredited NABERS assessor can help you understand your current rating and what improvements would be needed to reach the 4.5-star threshold. A commercial energy audit is often the first step in identifying the most cost-effective upgrade pathway.
NABERS and Green Star
NABERS and Green Star are complementary rating systems. While NABERS measures actual operational performance based on measured data, Green Star rates design intent, construction quality, and operational management practices. Many high-performing buildings hold both a NABERS rating and a Green Star certification.
A strong NABERS rating can also contribute credits towards a Green Star Performance rating, creating a streamlined pathway for buildings pursuing both certifications. The accredited consultants in our network can advise on how to maximise benefits from both systems.
How NABERS Ratings Are Calculated
NABERS ratings are calculated using 12 months of actual consumption data (energy bills, water meters, waste audits) normalised for factors including building size, occupancy hours, climate zone, and equipment density. This normalisation ensures fair comparisons between buildings of different types, sizes, and locations.
The assessment must be conducted by a NABERS Accredited Assessor who collects the data, applies the relevant NABERS tool, and submits the rating for validation. The entire process typically takes 2 to 4 weeks once all data is available.
Get Connected with an Accredited NABERS Assessor
Whether you need a NABERS rating for CBD compliance, to attract quality tenants, or as part of a broader sustainability strategy, we connect you with accredited NABERS assessors across Australia. Fill in the form to receive obligation-free quotes. For more background on NABERS, see our comprehensive NABERS guide.