What Is a WERS Rating and Why Does It Matter for Australian Windows?

Quick Answer

A WERS rating (Window Energy Rating Scheme) measures the thermal performance of complete window systems, including the frame, glass and glazing configuration. It helps homeowners, builders and designers compare how different windows may influence heating and cooling energy use in Australian homes.

Introduction

Windows play an important role in the energy performance of Australian homes.

A well-designed window system can help improve:

• Indoor comfort
• Natural lighting
• Ventilation
• Heating and cooling efficiency
• Overall building performance

However, comparing window performance can be challenging because many factors influence the final result.

This is where WERS ratings provide valuable guidance.

Unlike looking only at the glass specification, WERS evaluates the complete window system, helping professionals make more informed decisions.

At MEICHEN Windows & Doors, we manufacture aluminium window and door systems designed for Australian residential and architectural projects, with performance considerations including glazing, frame design and climate suitability.

What Does WERS Stand For?

WERS stands for:

Window Energy Rating Scheme

It is a system designed to provide information about the energy performance of residential window products.

A WERS rating considers the complete window assembly, including:

• Glass type
• Aluminium frame
• Spacer system
• Window configuration
• Thermal properties

This provides a more realistic understanding of window performance compared with evaluating glass alone.

Why WERS Ratings Are Important

Windows can significantly influence a home’s thermal behaviour.

Poorly selected windows may contribute to:

• Excessive summer heat gain
• Winter heat loss
• Higher heating and cooling demand
• Reduced indoor comfort

A suitable window specification may help create a more balanced indoor environment.

How WERS Evaluates Window Performance

WERS considers several important performance factors.

1. U-Value

U-Value measures heat transfer through the complete window system.

Generally:

• Lower U-Value = less heat transfer

U-Value considers:

• Glass
• Frame
• Glazing system

It is an important indicator of insulation performance.

2. Solar Heat Gain Coefficient (SHGC)

SHGC measures how much solar energy enters through the window.

Generally:

• Lower SHGC reduces solar heat gain
• Higher SHGC allows more solar heat transmission

The ideal SHGC depends on:

• Climate zone
• Building orientation
• Shading design
• Energy strategy

3. Window Configuration

The complete window design affects performance.

Examples include:

• Fixed windows
• Sliding windows
• Awning windows
• Casement windows
• Double glazed systems

Different configurations may achieve different performance outcomes.

WERS Rating vs Glass Specification

A common misunderstanding is that better glass automatically means better window performance.

However, the complete system matters.

A window consists of:

• Frame
• Glass
• Seals
• Hardware
• Installation method

For example, two windows using similar glass may achieve different thermal performance because of differences in:

• Aluminium frame design
• Sealing systems
• Manufacturing quality

WERS and Double Glazing

Double glazing is commonly associated with improved window performance.

A double glazed window includes:

• Two glass panes
• An insulating cavity
• Spacer system

Potential benefits include:

• Reduced heat transfer
• Improved indoor comfort
• Better acoustic performance

However, the final WERS performance depends on the entire window system, not only the number of glass layers.

WERS and Low-E Glass

Low-E glass uses a specialised coating designed to control radiant heat transfer.

Depending on the selected glass type, Low-E glazing may help:

• Improve insulation
• Reduce unwanted solar heat
• Support energy efficiency goals

The correct Low-E specification depends on climate and project requirements.

WERS and Thermal Break Aluminium Windows

Aluminium is a strong and durable material widely used in Australian windows.

However, aluminium is also highly conductive.

Thermal break aluminium systems introduce an insulating barrier between aluminium sections.

Potential benefits include:

• Reduced heat transfer through frames
• Improved thermal performance
• Enhanced comfort

For projects with higher energy efficiency objectives, thermal break systems may be considered.

WERS and NCC 2022 Energy Requirements

NCC 2022 increased the focus on residential energy efficiency.

Windows are an important part of the building envelope and should be considered together with:

• Insulation
• Orientation
• Ventilation
• Building materials
• Heating and cooling systems

A WERS rating can assist designers and builders when evaluating window performance as part of the overall energy assessment.

Choosing Windows According to Climate

Australia includes multiple climate zones.

Different regions may require different approaches.

Hot Climate Areas

Priorities may include:

• Solar control
• Lower heat gain
• Ventilation

Temperate Climate Areas

May require a balance between:

• Summer cooling
• Winter warmth

Cool Climate Areas

May prioritise:

• Heat retention
• Improved insulation

The best window specification depends on the project location.

Common Mistakes When Looking at WERS Ratings

Mistake 1: Choosing the Highest Rating Automatically

The highest rating is not always the most suitable.

The correct choice depends on the building design.

Mistake 2: Looking Only at One Number

Energy performance requires considering:

• U-Value
• SHGC
• Orientation
• Climate

Mistake 3: Ignoring Installation Quality

Even a high-performance window system requires correct installation to achieve expected results.

Australian Standards Related to Window Performance

AS 2047

AS 2047 covers performance requirements for external windows and glazed doors, including:

• Structural performance
• Air infiltration
• Water penetration resistance

AS 1288

AS 1288 provides requirements for:

• Glass selection
• Safety glazing
• Installation considerations

NCC 2022

NCC 2022 includes requirements related to building energy efficiency and overall residential performance.

Why Choose MEICHEN Windows & Doors?

MEICHEN Windows & Doors manufactures customised aluminium window and door systems for Australian projects.

Our solutions include:

• Aluminium awning windows
• Sliding windows
• Casement windows
• Sliding doors
• Double glazing options
• Low-E glass solutions
• Thermal break systems

We support:

• Builders
• Architects
• Developers
• Homeowners

with project-specific window solutions.

Frequently Asked Questions

Is a higher WERS rating always better?

Not necessarily. The appropriate rating depends on the building location, orientation and energy requirements.

Does WERS test only glass?

No. WERS evaluates the complete window system, including the frame and glazing configuration.

Are aluminium windows energy efficient?

Yes. With appropriate frame design, glazing and installation, aluminium windows can achieve excellent energy performance.

Do double glazed windows have better WERS ratings?

Many double glazed systems achieve improved thermal performance, but the final rating depends on the complete window design.

Do thermal break windows improve WERS performance?

Thermal break systems may improve overall thermal performance by reducing heat transfer through aluminium frames.

Conclusion

WERS ratings provide valuable information when selecting aluminium windows for Australian homes.

However, window performance should always be evaluated as part of a complete building design.

Important considerations include:

• Frame design
• Glass selection
• U-Value
• SHGC
• Climate
• Orientation
• Installation quality

By understanding WERS ratings, homeowners, builders and architects can make better-informed decisions when selecting aluminium window systems.

MEICHEN Windows & Doors provides customised aluminium window solutions designed to support modern Australian residential construction with a focus on performance, quality and long-term value.