Do Aluminium Windows Meet the 7-Star Energy Rating Requirements in Australia?

Can aluminium windows meet Australia’s 7-star energy rating requirements? Yes. Aluminium windows can be specified for homes designed to achieve a 7-star NatHERS thermal performance rating, provided the complete building design and selected window systems satisfy the applicable energy-efficiency requirements.

The important distinction is that a 7-star rating applies to the home’s overall thermal performance, not to an individual aluminium window.

For builders, architects, developers and homeowners in Melbourne, achieving a compliant design involves selecting the appropriate combination of aluminium frames, glazing, insulation, shading and building orientation.

What Is the 7-Star Energy Rating Requirement in Australia?

The National Construction Code introduced stronger residential energy-efficiency requirements through NCC 2022.

These include a minimum thermal performance equivalent to 7 stars under the Nationwide House Energy Rating Scheme (NatHERS), together with Whole of Home energy requirements.

Victoria’s updated requirements commenced on 1 May 2024.

The applicable NCC edition, transitional arrangements and compliance pathway must be confirmed for each project.

What Does a 7-Star NatHERS Rating Mean?

NatHERS assesses the predicted thermal performance of a home.

It considers how effectively the building maintains comfortable indoor temperatures while limiting the need for heating and cooling.

The assessment considers the complete building, including:

• Windows and doors
• Insulation
• Roof and wall construction
• Building orientation
• Shading
• Glazing area
• Thermal characteristics of building materials
• Climate

A window contributes to the result but doesn’t determine the rating by itself.

Can Aluminium Windows Be Used in a 7-Star Home?

Yes.

Aluminium windows are suitable for consideration in homes targeting 7-star NatHERS performance.

However, the aluminium system and glazing must be selected to meet the building’s energy assessment.

Depending on the project, suitable solutions may include:

• Double-glazed aluminium windows
• Low-E glazing
• Thermally broken aluminium systems
• Appropriate solar-control glass
• Carefully designed window sizes
• External shading

The required specification varies between buildings.

Are Aluminium Windows Energy Efficient Enough for Modern Australian Homes?

They can be.

Modern aluminium window systems offer different levels of thermal performance.

Conventional aluminium conducts heat relatively efficiently, but appropriate glazing can improve overall window performance.

Thermally broken aluminium systems provide an additional option for reducing heat transfer through the frame.

The most useful comparison is the verified performance of the complete window rather than the frame material alone.

Is Double Glazing Mandatory for a 7-Star Home?

No.

Double glazing is not universally mandatory simply because a home must achieve a 7-star NatHERS rating.

A well-designed building may be able to achieve the required rating with some single glazing.

However, double glazing is frequently considered because it can significantly improve window insulation.

The correct glass specification should come from the building’s energy assessment.

Do You Need Thermally Broken Aluminium Windows for 7 Stars?

Not necessarily.

Thermally broken aluminium can improve frame insulation, but there is no universal requirement that every aluminium window in a 7-star home must have a thermal break.

The project may achieve the required performance through other suitable combinations of glazing, framing and building design.

For homes with extensive glazing or demanding thermal targets, thermally broken systems may be particularly useful.

What Is the Difference Between NatHERS and WERS?

NatHERS and WERS assess different things.

NatHERS evaluates the predicted thermal performance of a home.

WERS, the Window Energy Rating Scheme, provides performance information for window systems.

Window performance data can be used in building energy assessments to help select appropriate products.

A window’s WERS heating or cooling star rating should not be confused with a home’s NatHERS star rating.

What Is a Window U-Value?

U-value measures the rate of heat transfer through a building element.

For windows, a lower U-value generally indicates better insulation.

When comparing aluminium windows, request the whole-window U-value, which includes the influence of both frame and glazing.

A low glass-only U-value doesn’t automatically mean the complete window has the same performance.

What Is SHGC and Why Does It Matter?

SHGC stands for Solar Heat Gain Coefficient.

It measures how much solar heat passes through the window.

A lower SHGC generally means less solar heat enters the building.

However, the ideal SHGC depends on orientation, climate and shading.

Some windows may benefit from allowing useful winter sunlight into the home, while others may require stronger solar control.

Is Low-E Glass Required for 7-Star Aluminium Windows?

Not universally.

Low-E glass is one way to improve glazing performance.

It uses a specialised coating that influences radiant heat transfer.

Depending on the building design, Low-E glazing may be recommended to help achieve the required thermal performance.

The exact coating should be selected according to the energy assessment and window orientation.

Which Aluminium Window Frames Are Best for 7-Star Homes?

There isn’t one universal best aluminium frame.

The most appropriate system depends on:

• Required whole-window U-value
• Required SHGC
• Window dimensions
• Architectural appearance
• Glass specification
• Budget
• Available manufacturer performance data

Conventional and thermally broken aluminium systems should be compared against the project’s requirements.

Can Sliding Aluminium Windows Meet 7-Star Home Requirements?

Yes, provided the selected sliding window system meets the performance requirements identified for the project.

Different window configurations can have different thermal and air-leakage characteristics.

The energy assessor should be provided with the actual system information rather than a generic description.

Can Aluminium Sliding Doors Be Used in 7-Star Homes?

Yes.

Large sliding doors are common in modern architectural homes.

However, large glass areas can significantly influence thermal performance.

For large doors, consider:

• Frame system
• Double glazing
• Low-E glass
• U-value
• SHGC
• Door dimensions
• Air sealing
• External shading

The selected system must also satisfy applicable structural and weather-performance requirements.

Are Bifold Doors Suitable for 7-Star Homes?

They can be.

Bifold doors may create large openings with substantial glazing areas.

Their thermal performance depends on the complete system, including glass, framing and seals.

Where high thermal performance is required, system selection becomes particularly important.

Do Large Windows Make Achieving 7 Stars More Difficult?

They can.

Large glass areas may increase unwanted heat loss or solar heat gain, depending on their orientation and specification.

However, large windows can also provide useful daylight and winter solar gain when appropriately designed.

The goal is not necessarily to minimise glazing.

It is to balance architectural design with thermal performance.

Does Window Orientation Affect the 7-Star Rating?

Yes.

Orientation is an important part of energy-efficient design.

In Melbourne, north-facing windows may be positioned to capture useful winter sunlight.

East- and west-facing glazing can present different solar-control challenges.

The best glass specification may therefore vary across the building.

Can Aluminium Window Shrouds Improve Energy Efficiency?

Architectural aluminium window shrouds can contribute to external shading when correctly designed.

Depending on their depth, geometry and orientation, shrouds may reduce direct sunlight reaching the glass.

However, shading effectiveness varies.

Window shrouds should be incorporated into the building’s architectural and energy-performance design rather than assumed to provide a particular energy rating.

Are 7-Star Aluminium Windows More Expensive?

Higher-performance aluminium window specifications can cost more than basic systems.

The additional cost may relate to:

• Double glazing
• Low-E coatings
• Thermally broken frames
• Specialised seals
• Hardware
• Larger or more complex glazing

However, not every project requires the most expensive system.

A coordinated building design may help achieve the required performance more economically.

How Much Do 7-Star Compliant Aluminium Windows Cost in Melbourne?

There isn’t one price for a “7-star aluminium window” because 7 stars refers to the home, not an individual window product.

Pricing depends on the actual window schedule and required performance.

The best approach is to provide the window supplier with:

• Architectural drawings
• Window dimensions
• Window configurations
• Required U-values
• Required SHGC values
• Glazing specifications
• Relevant energy-assessment documentation

This enables a quotation based on the actual project requirements.

Can a 7-Star Home Use Standard Aluminium Windows?

Potentially.

Some building designs may achieve the required energy performance while incorporating conventional aluminium windows.

However, this cannot be assumed for every project.

The building’s energy assessment determines whether the proposed combination of windows and other building elements is appropriate.

Can You Achieve 7 Stars Without Double Glazing Every Window?

Potentially, yes.

Some projects may use different glazing specifications across different elevations or rooms.

For example, the energy assessor may identify where improved glazing has the greatest benefit.

The final design must still satisfy the relevant compliance requirements.

What Is the Whole of Home Energy Rating?

The Whole of Home assessment considers predicted energy use associated with fixed building services and relevant energy generation.

It is separate from the NatHERS thermal star rating.

Depending on the applicable compliance pathway, the assessment can consider:

• Heating and cooling
• Hot water
• Lighting
• Certain fixed equipment
• Solar generation and storage

A home’s thermal star rating and Whole of Home requirements must be considered separately.

Do Existing Homes Need to Achieve 7 Stars?

Not every existing home is automatically required to be upgraded to 7 stars.

However, significant renovations, alterations and extensions may trigger current energy-efficiency requirements.

The requirements depend on the scope of work, the applicable regulations and the building approval process.

For renovation projects, consult the relevant building surveyor or energy assessor before selecting replacement windows.

Are 7-Star Requirements the Same Across Australia?

Not necessarily.

The NCC provides a national framework, but adoption dates, variations and transitional arrangements can differ between states and territories.

The applicable NCC edition and local requirements should be checked for each project.

This is particularly important for builders and developers operating across multiple states.

What Information Does an Energy Assessor Need About Aluminium Windows?

The assessor may require:

1. Window manufacturer and system
2. Window configuration
3. Frame type
4. Glazing specification
5. Whole-window U-value
6. Whole-window SHGC
7. Window dimensions
8. Orientation
9. Relevant shading information

Providing accurate information early can reduce the need for product changes later.

Can You Change Window Systems After the NatHERS Assessment?

Possibly, but the replacement system must be assessed against the approved design requirements.

Changing from one aluminium system to another may alter the U-value or SHGC.

Even if the replacement window looks identical, its thermal performance may differ.

Any proposed substitution should be checked with the energy assessor or relevant design professional before ordering.

What Should Builders Look for When Ordering Aluminium Windows?

Builders should avoid ordering windows based on appearance or dimensions alone.

Confirm that the quotation matches:

• Architectural plans
• Window schedule
• Energy report
• Glass requirements
• Performance specifications
• Applicable building requirements

Shop drawings should be reviewed and approved before manufacture.

This helps reduce the risk of ordering windows that don’t match the project’s approved specification.

What Should Architects Specify for Energy-Efficient Aluminium Windows?

Architects should coordinate the window schedule with the project’s thermal-performance assessment.

Specifications should identify the required performance rather than relying solely on generic terms such as “double glazed” or “energy efficient.”

Relevant details may include whole-window U-value, SHGC, glazing, frame system, dimensions and applicable performance standards.

This makes it easier for suppliers to propose suitable systems and for builders to compare quotations.

Can Aluminium Windows Meet Higher Than 7-Star Requirements?

Yes.

Aluminium window systems can be considered for buildings targeting higher thermal performance.

However, higher-performing homes may require more demanding combinations of:

• Thermally broken framing
• High-performance glazing
• Advanced insulation
• Airtightness measures
• Shading
• Building-envelope design

The appropriate specification depends on the overall design and assessment.

How Can You Reduce the Cost of Windows for a 7-Star Home?

The most effective approach is to coordinate window design early.

Consider:

• Selecting window sizes carefully
• Using appropriate configurations
• Avoiding unnecessary glass specifications
• Designing effective external shading
• Comparing verified window performance
• Standardising systems where practical
• Finalising the energy assessment before ordering

A lower-cost window that doesn’t satisfy the approved specification can become an expensive mistake.

Energy-Efficient Aluminium Windows from EZ Windows

EZ Windows provides aluminium window and door solutions for builders, architects, developers and homeowners across Melbourne and Victoria.

Depending on the project requirements and selected supplier systems, options can include:

• Fixed aluminium windows
• Awning aluminium windows
• Sliding aluminium windows
• Double glazing
• Low-E glazing
• Thermally improved aluminium systems
• Sliding doors
• Stacking doors
• Bifold doors
• Architectural aluminium window systems

For projects targeting 7-star NatHERS performance, the relevant window schedule and energy-assessment requirements can be reviewed to identify suitable product options.

EZ Windows supplies window systems to the specified requirements; the project’s designer, energy assessor and relevant building professionals remain responsible for determining and verifying building compliance.

So, Can Aluminium Windows Meet Australia’s 7-Star Energy Requirements?

Yes. Aluminium windows can form part of a home that achieves a 7-star NatHERS rating.

The key is selecting the right complete window system.

For many projects, this may involve:

Appropriate aluminium framing + double glazing + Low-E glass + verified U-value and SHGC + effective shading.

Thermally broken aluminium can provide additional performance where required.

However, there is no single aluminium window that automatically makes a home 7-star compliant.

The entire building must be assessed.

For builders, architects and homeowners, the most effective approach is to coordinate the energy assessment and window specification before ordering.

Architectural precision, designed to perform.

Do It Easy @ EZ Windows.