NatHERS Star Ratings
What Is a 6 Star NatHERS Rating?
A 6 Star NatHERS rating was a long standing residential benchmark in Australia. It still helps explain thermal performance, but many new homes now need to be assessed against higher current requirements.
6 Star NatHERS in brief
A 6 Star NatHERS rating indicates good thermal performance on the NatHERS 0 to 10 star scale, but it is no longer the main benchmark for many new homes under current residential energy settings. Whether 6 Stars is acceptable depends on the project location, approval timing, building type and applicable compliance pathway.
What 6 Stars means in practice
A 6 Star NatHERS rating means the home has been modelled to achieve a moderate to good level of thermal performance. It indicates that the design should need less heating and cooling than a lower rated home in the same climate.
The rating is based on the home’s design and building fabric. This includes orientation, layout, insulation, glazing, shading, roof colour, floor construction, wall and roof systems, construction materials and local climate.
A 6 Star rating does not mean the home will be uncomfortable. It means the home has reached a certain thermal performance level on the NatHERS scale. However, compared with a 7 Star home, it will generally require more heating and cooling to maintain comfort.
Why 6 Stars used to be such a common benchmark
For many years, 6 Stars was the familiar minimum thermal performance benchmark for many Australian residential projects. It became part of the way homeowners, designers, builders and assessors talked about new home energy performance.
That history is why many older pages, approvals, reports and industry conversations still refer to 6 Star NatHERS. In some project contexts, it may still be relevant because of approval timing, transitional arrangements or specific jurisdictional pathways.
The important point is that 6 Stars should not be assumed to be the current target for every new home. The applicable requirement needs to be checked against the project’s location, building class and approval pathway.
The practical point
6 Stars is best understood as an important historical and transitional benchmark.
For many current new home projects, the project team should confirm whether a 7 Star or equivalent pathway now applies.
6 Star vs 7 Star NatHERS
The difference between 6 Star and 7 Star NatHERS is not just a small label change. A 7 Star home is generally expected to need less heating and cooling than a 6 Star home to maintain comfort in the same climate.
In design terms, moving from 6 Stars to 7 Stars often requires more careful coordination of the building fabric. Window placement, glazing performance, shading, insulation, roof colour, floor construction and thermal mass may all become more important.
For a detailed explanation of the higher benchmark, see our guide to what a 7 Star NatHERS rating means.
Is 6 Star NatHERS still compliant?
Whether 6 Star NatHERS is still compliant depends on the project. Australia’s residential energy requirements have changed over time, and the current pathway may depend on the state or territory, approval date, project type and transitional rules.
For many new homes under updated NCC 2022 settings, a 7 Star thermal performance requirement or equivalent is now the key benchmark, together with Whole of Home energy requirements. However, some projects may still sit under earlier approvals or different arrangements.
Because of this, 6 Star NatHERS should be treated carefully. It may be relevant to older projects, existing approvals, specific transition periods or explanatory content, but should not automatically be treated as the current target for a new project.
When 6 Stars may still come up
• Older residential approvals or legacy project documentation
• Transitional projects lodged under earlier requirements
• Older website content, reports or industry references
• Renovation or alteration pathways where requirements are project specific
• Comparisons explaining the shift from 6 Star to 7 Star performance expectations
What affects whether a home reaches 6 Stars?
A 6 Star result is shaped by the same thermal design factors that influence any NatHERS rating. The home’s climate, orientation, glazing, insulation, shading and construction details all affect the final result.
Key rating factors include:
• Orientation and solar exposure
• Window size, placement, frame type and glazing performance
• Ceiling, roof, wall and floor insulation
• Eaves, awnings, balconies and other shading
• Roof colour and external surface properties
• Construction type, thermal mass and floor system
• Local NatHERS climate zone
The same home may perform differently in different climate zones. A 6 Star pathway in one location may require different design decisions from a 6 Star pathway somewhere else.
How 6 Stars relates to BASIX and Whole of Home
In NSW, NatHERS modelling may support the thermal performance component of BASIX. If a project refers to 6 Star NatHERS, the BASIX and approval context should be checked carefully to confirm which standard applies.
Whole of Home is separate from the thermal star rating. While NatHERS thermal performance focuses on heating and cooling needs created by the building fabric, Whole of Home considers broader energy use, systems, solar and batteries where applicable.
This means a project should not only ask whether it reaches 6 Stars. It should ask which thermal standard applies and whether Whole of Home requirements also need to be addressed.
Design considerations for Australian homes
A 6 Star rating can help explain the basics of thermal performance, but current design conversations increasingly need to consider higher performance expectations. Homes that only just meet older benchmarks may struggle under newer requirements without design changes.
For projects moving toward 7 Stars, the design may need more attention to glazing distribution, shading depth, insulation continuity, roof colour, floor construction and climate response. These changes are easier to resolve early than after documentation is complete.
The aim is not simply to add more products. It is to make the home’s building fabric work more intelligently with its site and climate.
Working with Certified Energy
Certified Energy provides NatHERS assessments for new homes, townhouses and multi residential projects across Australia. Our team can help clarify whether a project sits under older 6 Star expectations, current 7 Star settings or a specific transitional pathway.
We can also help project teams understand how the rating is influenced by insulation, glazing, shading, orientation, roof colour, climate zone and construction details. Where relevant, we connect the assessment with related requirements such as NatHERS, 7 Star Rating, BASIX and Whole of Home.
For a broader explanation of the rating framework, visit our NatHERS Knowledge Hub.
FAQ
What is a 6 Star NatHERS rating?
A 6 Star NatHERS rating indicates good thermal performance on the NatHERS scale. It means the home is expected to need less heating and cooling than lower rated homes, but it is generally below the current 7 Star benchmark for many new homes.
Is 6 Star NatHERS still compliant?
It depends on the project. Some older or transitional projects may still refer to 6 Stars, but many current new homes need to consider 7 Star or equivalent requirements under updated residential energy settings.
What is the difference between 6 Star and 7 Star NatHERS?
A 7 Star rating generally indicates stronger thermal performance than a 6 Star rating. It means the home is expected to need less heating and cooling to remain comfortable in the same climate.
Why do older pages still mention 6 Star NatHERS?
6 Stars was a common benchmark for many years, so it still appears in older content, approvals and industry references. Current project requirements should always be checked against the relevant jurisdiction and approval timing.
Can a 6 Star design be improved to 7 Stars?
Often, yes. Improvements may involve glazing changes, better shading, insulation upgrades, roof colour changes, revised construction details or other building fabric adjustments, depending on the design and climate zone.
