If you’re involved in the design, construction or operation of buildings in Australia, you’ve likely come across both NatHERS and NABERS. While they are often mentioned together, they serve fundamentally different purposes and apply at different stages of a building’s lifecycle.
Understanding the distinction between these two frameworks is essential for ensuring compliance requirements under the National Construction Code (NCC), improving energy performance, and making informed building design or investment decisions.
This guide provides a detailed comparison of NatHERS vs NABERS, explaining how each system works, when they apply, and how they fit within Australia’s broader energy efficiency framework.
Table of Contents
At A Glance
- NatHERS is a design-stage thermal performance assessment for residential buildings, and applies to houses and apartments
- NABERS measures environmental performance of a building during operation based on real energy usage, and applies to commercial buildings and large-scale developments
- NatHERS uses simulation modelling software, while NABERS uses measured utility and metering data
- NatHERS is used for NCC compliance and building approval, while NABERS is used for benchmarking, disclosure, and ESG reporting
What Is NatHERS?
NatHERS (Nationwide House Energy Rating Scheme) is Australia’s primary tool for assessing the thermal performance of residential buildings at the design stage.
It evaluates how efficiently a home maintains comfortable indoor temperatures throughout the year based on the building design, materials and local climate zone conditions.
NatHERS assessments are conducted using accredited thermal modelling software such as FirstRate5, AccuRate or HERO. These rating tools simulate how a dwelling performs across a full year (8,760 hours), calculating the energy required for heating and cooling under standardised conditions.
Key Characteristics of NatHERS:
- Applies to new homes, renovations and multi-dwelling residential developments
- Produces a star rating from 0 to 10
- Focuses on building envelope, including:
- Wall, roof, and floor construction
- Insulation levels
- Window placement, size, type, and glazing performance
- Building orientation and solar exposure
- Shading and eaves design
- Air leakage assumptions
- Building materials
- Used to demonstrate compliance with the National Construction Code (NCC)
- Assessed before construction begins
- It calculates the annual heating and cooling loads required to maintain thermal comfort
A higher NatHERS star rating indicates that a home requires less energy for heating and cooling, resulting in improved comfort and lower operational costs over time.
Under NCC 2022, most new residential buildings must achieve a minimum 7-star rating, making NatHERS a central component of residential compliance.
What Is NABERS?
NABERS (National Australian Built Environment Rating System) measures the actual operational performance of buildings once they are in use.
Unlike NatHERS, which is based on modelling assumptions, NABERS ratings are derived from real measured data, including energy consumption, water efficiency, waste generation and indoor environmental quality.
Key Characteristics of NABERS:
- Applies to existing buildings, primarily commercial (offices, shopping centres, hotels, apartments)
- Produces a rating from 0 to 6 stars
- Based on measured utility data and building operation
- Reflects real-world performance
- Used for benchmarking, disclosure and performance improvement
For example, a NABERS Energy rating for an office building is calculated using:
- Actual electricity and gas bills
- Occupancy levels
- Hours of operation
- Climate data adjustments
The higher the NABERS star rating, the lower the greenhouse gas emissions of the building will be.
This provides a verified measure of environmental performance and how efficiently a building is being run, rather than how it was designed to perform.
The Fundamental Difference: Design vs Operational Performance
The most important distinction between NatHERS and NABERS lies in what they measure and when they are used.
- NatHERS = Predicted performance (design stage)
- NABERS = Actual performance (operational stage)
NatHERS answers:
How energy-efficient is this building likely to be based on its design?
NABERS answers:
How energy-efficient is this building in reality?
This difference has practical implications.
A building can:
- Achieve a high NatHERS rating but perform poorly in NABERS due to inefficient systems or occupant behaviour
- Have a moderate design performance but achieve a strong NABERS rating through efficient operation and management
Understanding both systems provides a more complete picture of building performance across its lifecycle and is critical for understanding why the two systems cannot be used interchangeably.
How NatHERS and NABERS Fit Within the NCC Framework
Both systems sit within Australia’s broader regulatory and sustainability landscape, but they serve different roles.
NatHERS and the NCC
NatHERS is directly linked to NCC compliance for residential buildings. It is one of the most widely used pathways to demonstrate that a design meets minimum energy efficiency requirements, and must be carried out by NatHERS accredited assessors.
Under NCC 2022:
- A minimum 7-star NatHERS rating is required
- A Whole of Home energy rating is also introduced
- Thermal performance must meet climate-specific benchmarks
Without a compliant NatHERS assessment and star rating, most residential projects cannot proceed to approval.
NABERS and Regulatory Requirements
NABERS is not typically used for design-stage compliance. Instead, it plays a role in:
- Commercial Building Disclosure (CBD) requirements
- Government leasing standards
- ESG reporting and sustainability targets
- Ongoing performance benchmarking
For example:
- Office buildings over a certain size must disclose their NABERS Energy rating when sold or leased
- Government tenants often require minimum NABERS ratings for occupancy
This makes NABERS a critical tool in the commercial property sector, particularly for investors and asset managers.
Key Differences Between NatHERS and NABERS
|
Feature
|
NatHERS
|
NABERS
|
|---|---|---|
|
Stage
|
Design
|
Operation
|
|
Building Type
|
Residential
|
Primarily Commercial
|
|
Rating Scale
|
0–10 stars
|
0–6 stars
|
|
Data Source
|
Modelled simulation
|
Measured performance
|
|
Focus
|
Thermal envelope
|
Whole building performance
|
|
Purpose
|
NCC compliance
|
Benchmarking & disclosure
|
|
Timing
|
Pre-construction
|
Post-occupancy
|
Can NatHERS and NABERS Apply to the Same Building?
Yes – while NatHERS and NABERS serve different purposes, they can both apply to the same project, just at different stages and often to different parts of the building.
For example:
- An apartment building may use NatHERS during the design phase to assess the thermal performance of individual dwellings and demonstrate NCC compliance
- Once constructed and occupied, the same building may receive a NABERS rating to measure the operational performance of common areas, such as corridors, lifts, lighting, and central services
In some cases, NABERS may also assess the building more broadly where sufficient operational data is available, particularly in large multi-residential or mixed-use developments.
This overlap is becoming increasingly important as the industry shifts toward a whole-of-life approach to building performance. Rather than focusing solely on design compliance, there is growing emphasis on how buildings actually perform in use, closing the gap between predicted and real outcomes.
You’ll also see both systems referenced within broader sustainability frameworks, such as Green Star, where:
- NatHERS contributes to design-stage performance modelling
- NABERS supports ongoing performance verification and benchmarking
In this context, NatHERS and NABERS are not competing system, but rather complementary tools that together provide a more complete picture of a building’s energy performance and environmental footprint, from concept through to operation.
Limitations of Each System
Understanding the limitations of each system is important when interpreting results.
NABERS Limitations:
- Influenced by tenant behaviour and occupancy patterns
- Cannot isolate building design from operational performance
- Requires 12 months of operational data
- Not suitable for early design decisions
NatHERS Limitations:
- Does not account for appliances or occupant behaviour
- Assumes standardised usage patterns
- Focuses only on heating and cooling loads
- May not reflect actual energy bills
Because of these limitations, relying on one system alone does not provide a complete picture of energy performance.
Why the Difference Matters for Your Project
Understanding the difference between NatHERS and NABERS is not just about building compliance, it directly influences how you approach design, construction, and long-term building performance.
For Residential Projects
NatHERS plays a critical role in shaping outcomes early in the design process. Decisions made at this stage, such as orientation, glazing, and insulation, can significantly impact both compliance and long-term energy efficiency.
A well-optimised NatHERS assessment can:
- Reduce the need for costly design changes during approvals
- Improve thermal comfort and livability
- Lower ongoing heating and cooling requirements
Because NatHERS is assessed before construction, it provides an opportunity to improve performance when it is most cost-effective to do so.
For Commercial Buildings
NABERS shifts the focus from design to real-world performance and accountability.
For building owners and asset managers, NABERS ratings can:
- Influence leasing potential and tenant demand
- Impact asset value and marketability
- Identify inefficiencies in building operation
- Support ESG reporting and sustainability targets
In this context, performance is not theoretical, it is measurable, reportable, and often publicly disclosed.
For Developers and Investors
For larger or mixed-use projects, understanding both systems enables a whole-of-life performance strategy.
Rather than treating compliance and performance as separate considerations, aligning design intent (NatHERS) with operational outcomes (NABERS) can:
- Improve long-term asset performance
- Reduce operational costs over the building lifecycle
- Minimise the performance gap between design and reality
This is increasingly important as regulatory frameworks and market expectations shift toward measurable, verifiable building performance.
Conclusion: Design Performance vs Real-World Outcomes
NatHERS and NABERS represent two critical but distinct aspects of building energy efficiency and performance.
As the industry moves toward more rigorous sustainability standards, the gap between designed performance and actual performance is becoming increasingly important.
Projects that perform well across both systems are typically those that:
- Integrate energy efficiency early in design
- Use high-quality construction and materials
- Maintain efficient systems and building management practices
Understanding how NatHERS and NABERS work together allows developers, designers and building owners to move beyond minimum compliance and focus on long-term performance, cost efficiency and occupant comfort.
Get Expert Guidance on NatHERS Compliance
If you’re planning a residential project and need to meet NCC energy efficiency requirements, working with an experienced NatHERS accredited assessor is essential.
Green Choice Consulting provides accurate, compliant NatHERS certificates across Australia. Our team works closely with architects, builders and developers to optimise designs, reduce compliance risk and deliver cost-effective outcomes.
Enquire today to discuss your project and ensure your design meets energy efficiency requirements with confidence.
Frequently Asked Questions
Is NatHERS the same as NABERS?
No. NatHERS assesses predicted thermal performance at the design stage, while NABERS measures actual energy performance once a building is operational.
Which rating system is required for residential buildings?
NatHERS is typically required for residential buildings to demonstrate compliance with NCC energy efficiency provisions.
Do apartments use NatHERS or NABERS?
Apartments commonly use NatHERS during design for compliance. Larger apartment buildings may also receive NABERS ratings once operational, particularly for shared services.
Can a building have both a NatHERS and NABERS rating?
Yes. NatHERS applies at design stage, while NABERS applies after construction and occupancy.
Does a high NatHERS rating guarantee a high NABERS rating?
No. A well-designed building can still perform poorly if systems are inefficient or poorly managed. Likewise, operational efficiency can improve NABERS outcomes even in moderately rated designs.
Is NABERS mandatory?
In some cases, yes. NABERS ratings are required under Commercial Building Disclosure laws for certain office buildings and are often required for government tenancies.
What does NABERS measure that NatHERS does not?
NABERS measures actual energy use, water consumption, waste and indoor environment quality, while NatHERS focuses only on thermal performance.
What is the Whole of Home rating and how does it relate?
The Whole of Home rating expands beyond NatHERS by including appliances, lighting and renewable energy systems, bridging the gap between design and operational performance.
Which system is more accurate?
They measure different things. NatHERS is accurate for predicting thermal performance under standard conditions, while NABERS is accurate for measuring real-world performance.
Why do two similar buildings have different NABERS ratings?
Differences in occupancy, operating hours, equipment efficiency and building management practices can significantly impact NABERS results.
What energy assessment pathways are available for commercial buildings at the design stage?
- Section J Deemed-to-Satisfy (DTS): A prescriptive approach that sets minimum requirements for building fabric, glazing, services, and lighting
- JV3 (Performance Solution): A modelling-based pathway that demonstrates the proposed design performs as well as, or better than, a reference building
- J1V1 (Verification Method): Introduced under NCC 2022, this method uses whole-of-building energy modelling to assess overall performance
- Green Star: A voluntary sustainability rating system that assesses broader environmental performance, often incorporating energy modelling as part of the design process
- SDA (Sustainable Design Assessment): Required by some local councils (particularly in Victoria) for planning approval, focusing on sustainability outcomes at the design stage