NatHERS Explained
What Is a 7 Star Energy Rating?
A 7 Star Energy Rating usually refers to the thermal performance rating of a new home under NatHERS. It shows how well the home is expected to maintain comfortable indoor temperatures with less reliance on artificial heating and cooling.
In brief: A 7 Star NatHERS rating indicates stronger thermal performance than the previous 6 Star benchmark. Under NCC 2022, many new homes are now considered in the context of 7 Star NatHERS requirements and Whole of Home energy performance. Requirements can vary by project type, state, territory and approval timing, so project-specific advice is important.
What Does a 7 Star Energy Rating Mean?
A 7 Star Energy Rating means the home has been modelled to perform well thermally for its location and climate. In practical terms, the home should need less heating and cooling to stay comfortable than a lower-rated home of similar type and size.
The rating is not based on how the occupants use the home after it is built. It is based on the design, construction materials, glazing, insulation, orientation, shading and local climate conditions used in the NatHERS assessment.
How NatHERS Star Ratings Work
NatHERS, the Nationwide House Energy Rating Scheme, uses approved software to model the thermal performance of a home before it is built. The assessment estimates how much heating and cooling would be needed to keep the home comfortable across the year.
Homes are rated on a scale from 0 to 10 stars. A higher star rating generally means the home is expected to be more comfortable and require less energy for heating and cooling. A 10 Star home is designed to need very little additional heating or cooling to maintain comfort.
- 0 stars generally indicates very poor thermal performance.
- 6 stars was the previous common benchmark for many new homes.
- 7 stars is now the key minimum NatHERS context for many new residential projects under NCC 2022.
- 10 stars indicates a very high level of passive thermal performance.
Detailed Guide
7 Star NatHERS Rating
Learn what the 7 Star NatHERS requirement means for new residential projects.
Main Hub
NatHERS Knowledge Hub
Start here for NatHERS assessments, certificates, documents, costs and process.
What a 7 Star Rating Measures
A 7 Star NatHERS rating measures the thermal performance of the home’s building fabric. This means it focuses on how the dwelling itself responds to heat, cold, sun, shade and local climate conditions.
The assessment considers factors such as:
- orientation and site location
- floor plan and room layout
- wall, roof, floor and ceiling construction
- insulation levels
- window size, type, frame and glass performance
- shading from eaves, awnings, balconies and nearby structures
- ventilation openings and air movement
- local climate zone and seasonal conditions
The thermal star rating does not directly measure occupant behaviour, furniture, plug-in appliances or the way future residents choose to heat, cool or operate the home.
How Is a 7 Star Energy Rating Calculated?
A NatHERS assessor creates a thermal model of the proposed home using approved NatHERS software. The model is based on the project documentation, including plans, elevations, sections, construction details, window information and site data.
The software simulates how the home is expected to perform across the year in its specific climate. It calculates the heating and cooling load needed to maintain comfortable conditions, then converts that result into a star rating.
Because the rating is climate-specific, the same design may not achieve the same result in every location. A home that performs well in a mild coastal climate may need different design decisions in a hot inland climate, a cool temperate climate or an exposed site.
7 Star NatHERS and Whole of Home
The 7 Star NatHERS rating is only one part of the newer residential energy efficiency context. NCC 2022 also introduced Whole of Home energy performance, which considers major fixed appliances and energy systems such as hot water, heating and cooling equipment, solar and batteries.
This means a project may need to address both the thermal performance of the building fabric and the broader energy performance of the home. A strong NatHERS result can help reduce heating and cooling demand, while Whole of Home considers how the home’s fixed energy systems contribute to the overall result.
Why 7 Stars Matters for New Homes
A 7 Star rating is not just a compliance number. It usually reflects a home that has been designed with more attention to passive performance, climate response and comfort. This can reduce reliance on mechanical heating and cooling and help the home feel more stable across the seasons.
For project teams, understanding the 7 Star requirement early can help:
- reduce the risk of late redesign
- identify weak points in glazing, shading or insulation
- support better comfort outcomes for future occupants
- align the project with current residential energy compliance requirements
- make the NatHERS assessment process clearer and more efficient
What Can Affect Whether a Home Reaches 7 Stars?
A 7 Star result is rarely achieved through one design feature alone. The final rating usually depends on how the whole home works as a system.
Common factors that influence the result include:
- too much unshaded west-facing glazing
- poor orientation or difficult site constraints
- insulation levels that are not matched to the climate
- weak window performance or inappropriate frame selection
- dark roof colours in warmer climates
- limited shading or poor solar control
- thermal bridging, construction gaps or unresolved details
Early NatHERS advice can help identify which design changes are likely to make the biggest difference for the project, rather than relying on generic upgrades late in the process.
Need a 7 Star NatHERS Assessment?
Certified Energy can review your residential project documents and advise whether NatHERS, BASIX, Whole of Home or another residential energy compliance pathway applies.
Related Guides
- 7 Star NatHERS Rating
- NatHERS Knowledge Hub
- Whole of Home Energy Performance
- BASIX vs NatHERS: What Is the Difference?
FAQ
Is a 7 Star Energy Rating the same as NatHERS?
In most new home compliance discussions, a 7 Star Energy Rating usually refers to a 7 Star NatHERS thermal performance rating. NatHERS is the assessment pathway used to model how much heating and cooling the home is expected to need to stay comfortable.
Is 7 Star NatHERS required for every home?
Many new homes are now considered in the context of 7 Star NatHERS requirements under NCC 2022, but requirements can vary depending on state, territory, project type, approval pathway and timing. Project-specific advice is important.
What is the difference between 6 Star and 7 Star NatHERS?
6 Star NatHERS was the previous common benchmark for many new homes. A 7 Star NatHERS rating generally represents a higher level of thermal performance and usually requires more careful attention to orientation, glazing, insulation, shading and building fabric.
Does a 7 Star rating include appliances and solar?
The NatHERS thermal star rating focuses on the building fabric and heating and cooling demand. Whole of Home energy performance considers major fixed appliances and energy systems such as hot water, heating and cooling equipment, solar and batteries.
When should I organise a NatHERS assessment?
It is best to consider NatHERS before the design is fully locked in. Early assessment can make it easier to adjust glazing, shading, insulation, roof colour and construction details before late-stage redesign becomes more difficult.
