NatHERS Star Ratings
An 8 Star home goes beyond the common compliance conversation. It is about designing a home that is expected to need less heating and cooling while supporting stronger comfort and climate response.
An 8 Star NatHERS rating means a home has been modelled to perform at a higher level on the 0 to 10 star thermal performance scale. It generally indicates lower predicted heating and cooling demand than a 6 or 7 Star home in the same climate. Whether it is worth targeting depends on the site, design, budget, construction approach and long term performance goals.
An 8 Star NatHERS rating means the home is expected to have strong thermal performance for its local climate. The design should generally need less heating and cooling to remain comfortable than a lower rated home.
The rating is still based on the building fabric. It reflects how orientation, layout, insulation, glazing, shading, roof colour, floor construction, thermal mass and local climate work together in the model.
An 8 Star home does not mean the home will never need heating or cooling. It means the design is expected to moderate heat and cold more effectively before mechanical systems are needed.
For many new homes, the main compliance discussion is around the applicable minimum thermal performance requirement, often associated with 7 Star Rating pathways under current residential energy settings. An 8 Star target is generally a higher performance goal rather than the standard minimum for most projects.
That does not make it unnecessary. For some projects, aiming above the minimum can support better long term comfort, reduced heating and cooling demand and a more resilient design. For other projects, the cost, site constraints or design brief may make 8 Stars less practical.
The right question is not simply whether 8 Stars is required. It is whether the extra performance aligns with the project’s priorities, budget and design intent.
8 Stars should not be treated as a badge added at the end of design.
It is usually the result of early design coordination between site orientation, glazing, shading, insulation, construction materials and climate response.
An 8 Star home can be worth considering when the project is already aiming for better comfort, reduced reliance on heating and cooling or stronger long term performance. This can be especially relevant for owner occupiers who care about everyday comfort and running costs over many years.
Higher performance may also be valuable where the site has strong passive design opportunities. Good orientation, appropriate solar access, sensible glazing and integrated shading can make it easier to lift the rating without relying only on expensive product upgrades.
For homes that are already close to 8 Stars, small design refinements may be enough to reach the higher result. For homes that are struggling to reach minimum compliance, the path to 8 Stars may require more substantial changes.
An 8 Star target may be harder to justify when the project has major site or design constraints. Large unshaded glazing, difficult orientation, complex building forms, lightweight construction or limited shading opportunities can make the higher target more challenging.
It may also be less practical if the performance improvement requires changes that conflict with the project brief or budget. In some cases, reaching a strong 7 Star result with well coordinated Whole of Home decisions may be the more balanced pathway.
This is why early modelling is useful. It helps show whether 8 Stars is a realistic extension of the design or whether it would require disproportionate changes.
• Good orientation and climate responsive layout
• Carefully sized and placed glazing
• Strong external shading where needed
• Appropriate glazing and frame performance
• Well resolved ceiling, wall, roof and floor insulation
• Suitable roof colour and external surface choices
• Construction materials that suit the local climate
The main value of an 8 Star home is not only energy efficiency. It is also comfort. A better performing building fabric can help indoor temperatures remain more stable through hot and cold periods.
This may mean less reliance on heating and cooling, fewer uncomfortable rooms and a home that feels more settled across the day. The exact experience will still depend on how the home is used, how systems are operated and how well the construction matches the assessed design.
For households planning to live in the home long term, this comfort benefit can be just as important as the modelled reduction in heating and cooling demand.
The cost of achieving 8 Stars depends heavily on when the target is introduced. If the design is shaped with climate response from the beginning, the pathway can sometimes be efficient. If the target is added after the design is locked in, changes may be more expensive or disruptive.
Some improvements may involve specification upgrades, such as better glazing or additional insulation. Others may involve design changes, such as revising window sizes, improving shading or adjusting construction details. The best pathway depends on the modelled result, not a generic upgrade list.
A practical approach is to model the project, understand the gap between the current result and 8 Stars, then decide whether the improvements are worthwhile for the project.
An 8 Star home still sits within the broader NatHERS framework. The assessment uses accredited modelling to estimate the home’s heating and cooling needs in its climate and converts that result into a star rating.
In NSW, the thermal performance result may also need to align with BASIX documentation. If the project is aiming above minimum compliance, the design team should still make sure all commitments are realistic and carried through the drawings and specifications.
For broader energy outcomes, the home may also need to consider Whole of Home requirements. A strong thermal rating is important, but it is only one part of the overall residential performance picture.
An 8 Star target makes most sense when it supports the whole project, not when it creates late complexity for a marginal gain.
The best decision comes from modelling the design early and comparing the comfort, compliance and cost implications of the higher target.
An 8 Star pathway should respond to local climate. In cooler climates, heat retention, insulation and winter solar access may become more important. In hot climates, shading, solar control and reducing cooling loads may be the priority.
The home’s form also matters. Compact forms, well oriented living areas, shaded glazing and continuous insulation can all support stronger performance. Complex forms, exposed upper levels and large unshaded glass areas can make the pathway harder.
The earlier the target is discussed, the more likely it can be integrated without forcing awkward late changes.
Certified Energy provides NatHERS assessments for new homes, townhouses and multi residential projects across Australia. Our team can model the proposed design and help identify whether an 8 Star target is realistic, practical and aligned with the project brief.
Where needed, we can help project teams understand which design factors are influencing the result, including glazing, insulation, shading, orientation, roof colour, climate zone and construction details. We can also help 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.
An 8 Star home can be worth it when the design, budget and climate make higher thermal performance practical. It may support better comfort and lower heating and cooling demand, but the value depends on the project.
Is 8 Stars required for new homes?8 Stars is generally above the minimum thermal performance benchmark for many new homes. Whether it is worth targeting depends on the project brief, climate, budget and design strategy.
Does an 8 Star home need no heating or cooling?No. An 8 Star home may still need heating or cooling at times. The rating means the home is expected to need less heating and cooling than a lower rated home in the same climate.
Is 8 Stars expensive to achieve?It depends on the design. If the home is planned with good orientation, shading and building fabric from the beginning, the pathway may be more practical. If 8 Stars is added late, the required changes may be more costly.
What helps a home reach 8 Stars?Good orientation, appropriate glazing, external shading, strong insulation, suitable roof colour, climate responsive construction and early NatHERS modelling can all help support an 8 Star pathway.