8 Energy-Efficient Window Glass Types to Transform Your Home 

Energy-Efficient Windows for Australia’s Homeowners 

As global temperatures rise due to climate change, energy efficiency and sustainability have become increasingly important for both homes and businesses. Modern building designs now prioritise natural light for its health benefits, but balancing this with energy efficiency and selecting the right window glass types is crucial to managing heating and cooling costs effectively. 

Windows are essential in this process, as they allow sunlight to enter while regulating temperature. Choosing the right window glass types, such as double glazing, Low-E, or tinted glass, can improve insulation, maintain comfort, and reduce energy consumption. This article will help you navigate the different types of window glass, including their benefits, energy efficiency, and other important considerations for your space. 

Window Glass Types Used in Australia 

Laminated Glass 

Laminated glass is composed of two or more layers of glass bonded together with a tough interlayer, typically polyvinyl butyral (PVB). 

This construction provides enhanced safety, sound insulation, and UV protection. Laminated glass is commonly used in automotive windshields, skylights, soundproofing windows, and security glass due to its superior performance in these applications. However, in the context of home and commercial construction, it is valued for its superior performance in applications such as skylights, soundproofing windows, and security glass. 

Laminated glass used in residential and commercial settings range from 6 mm to 12 mm in thickness, depending on the specific requirements for safety, sound insulation, and UV protection. 

Double Pane Windows 

Double pane windows consist of two panes of glass separated by a gap filled with a gas, such as argon or krypton.

This gas-filled cavity helps to reduce heat transfer, making double-pane windows significantly more energy-efficient than single-pane windows. This improved energy efficiency can lead to lower heating and cooling costs, as well as a more comfortable indoor environment. 

Double-pane windows are generally more expensive than single-pane windows, but the long-term energy savings often justify the initial investment. The typical thickness of double-pane windows varies, but common options include 6 mm, 8 mm, and 10 mm. 

In Australia, where climate conditions can fluctuate significantly, double-pane windows are particularly beneficial in regions with cold winters or hot summers. Areas such as Tasmania, Victoria, and New South Wales often see significant energy savings from the installation of double-pane windows. Additionally, in coastal areas where noise pollution is a concern, double-pane windows can help to reduce noise transmission and create a quieter indoor environment. 

Triple Pane Windows 

Triple-pane windows, a premium option for energy efficiency and sound insulation, feature three panes of glass separated by two gas-filled cavities. This construction provides even higher levels of energy efficiency than double-pane windows, making them ideal for extreme climates or buildings where noise reduction is a priority. 

Triple-pane windows typically offer a 20-30% improvement in energy efficiency compared to double-pane windows. This is due to the additional layer of glass and the increased insulating properties of the two gas-filled cavities. Triple-pane windows can also reduce noise transmission by up to 50% or more, making them a popular choice for homes and commercial buildings located in noisy areas. 

These are generally more expensive than double-pane windows, the long-term energy savings and improved comfort often justify the investment. It’s important to consider factors such as local climate, building design, and personal preferences when deciding between double-pane and triple-pane windows. 

Tempered Glass 

Tempered glass is a heat-treated glass type, significantly stronger and more durable than traditional glass.

When broken, it shatters into small, blunt pieces rather than sharp shards, significantly reducing the risk of injury. This safety feature makes tempered glass an ideal choice for applications where safety is important. 

Tempered glass is commonly used in shower doors, tabletops, and doors, but its applications extend to a wide range of areas, including: 

• Automotive windows, especially the side and rear windows due to its impact resistance and safety benefits.
• Storefront windows for its strength and durability, making it suitable for commercial buildings.
• Glass railings for a sleek and modern look for balustrades and railings.
• Fireplaces and stoves because its heat resistance allows it to be used safely near heat sources.
• Safety glass, especially in areas where there is a risk of impact or breakage.

The increased strength and safety of tempered glass often justify its higher cost compared to traditional glass, but is arguably a reliable and safe choice. 

Low-E Glass 

Low-emissivity glass, or Low-E glass, is coated with a special film that reduces heat transfer. This coating reflects infrared radiation back into the room during the winter, helping to retain heat and reduce heating costs. In the summer, the coating reflects infrared radiation back outside, keeping the interior cooler and reducing cooling costs. 

Low-E glass offers several benefits, including: 

• Improved energy efficiency: Reduced heat transfer leads to lower energy bills. 
• Enhanced comfort: A more consistent indoor temperature improves comfort. 
• UV protection: The coating can help protect against harmful UV rays.
• Reduced glare: Low-E coatings can reduce glare, especially in rooms with large windows. 

Low-E glass is commonly used in windows, doors, and skylights, and it’s often combined with other glass types, such as laminated or tempered glass, to provide additional benefits like safety or sound insulation. 

Insulated Glass 

Insulated glass, which can be a double-pane or triple-pane glass, is a type of glass construction that features two or more panes of glass separated by a gas-filled cavity.

This cavity, typically filled with argon or krypton, acts as a thermal barrier that reduces heat transfer and improves energy efficiency. This means that insulated glass can lead to lower heating and cooling costs and a more comfortable indoor environment. 

Aside from its energy efficiency benefits, insulated glass also provides superior noise reduction. The gas-filled cavity helps to absorb and dampen sound waves, making it an ideal choice for homes and businesses in noisy areas.  

Key points to consider: 

• The thickness of the glass panes and the size of the gas-filled cavity can affect the overall energy efficiency and noise reduction performance. 
• Low-E coatings, typical of insulated glass units, further enhance their energy efficiency. 

Annealed Glass 

Annealed glass is the most common type of glass, produced by slowly cooling the glass after it is formed. This process helps to relieve internal stresses and improve its overall strength.  

While annealed glass is known for its brittle nature and can shatter into large pieces when broken, it remains a popular choice in applications where safety is less of a concern, like picture frames, windows in older buildings, interior doors, or other decorative elements. 

Annealed glass may not be the most suitable choice for applications requiring high levels of safety, its affordability and versatility make it a popular option for many. It’s typically colourless, but it can be tinted or coloured to create various aesthetic effects. 

It is also available in a wide range of thicknesses, from thin sheets used for decorative purposes to thicker panes for windows and doors. 

Tinted Glass 

Tinted glass has been coloured or treated to reduce the transmission of visible light. For Brisbane’s hot climate, homeowners prefer a medium to dark tint of around 20% to 50% VLT.

This helps reduce heat and glare while maintaining privacy. While car tints have limits, it is not the same for homes, and there is no legal limit on how dark you can tint your home windows. 

However, while there are no specific regulations regarding window tinting darkness levels for residential properties in Queensland, it’s essential to consider Building Code of Australia (BCA) requirements. 

Excessively dark tinting can pose safety risks, especially during emergencies, as it may impede visibility. Adequate natural light is mandated for habitable rooms in the BCA, and excessive tinting could compromise this requirement. 

Experts recommend staying within specific parameters for residential window tinting. 

• Visible Light Transmission (VLT) of 15-30% offers a good balance of privacy, energy efficiency, and natural light.
• North-facing windows work well with a higher VLT (30-50%) to maximise natural light. 
• South-facing windows are expected to have a darker tint (15-30%) to help reduce glare and heat gain. 

Your specific needs may vary depending on your home’s orientation, local climate, and personal preferences. While you have more freedom in tinting your residential windows compared to vehicles, it’s crucial to balance aesthetics with safety and compliance. 

Choosing the Right Glass Type 

When selecting the ideal glass type for your windows, several factors should be considered: 

Climate 

Choosing window glass types often put thickness as a crucial factor for maintaining optimal indoor temperature and energy efficiency in different climates. Here’s a general guideline based on climate zones in the Building Code of Australia (BCA): 

• Warm Climates (Zone 1-3) is best for double glazing with 6mm to 8mm glass thickness is recommended to reduce heat gain and improve insulation. Low-E coatings can further enhance energy efficiency by reflecting heat back into the room during the winter and out of the room during the summer.
• Mild Climates (Zone 4-6) will be fine with single glazing for 4mm to 6mm glass, but double glazing can provide additional insulation and energy savings.
• Cold Climates (Zone 7-8) require double or triple glazing with 6mm+ glass thickness is recommended to minimise heat loss. Argon-filled cavities can significantly improve insulation performance. 

However, for specific requirements tailored to your region, building type, and personal preferences, it is best to consult local building codes and professionals. 

Energy efficiency goals 

If energy efficiency is a priority, consider insulated glass, triple-pane windows, or low-E glass. 

Insulated glass, whether double-pane or triple-pane, significantly improves energy efficiency by trapping heat inside during the winter and keeping it out during the summer. Studies have shown that insulated glass can reduce energy consumption by up to 25% compared to single-pane glass. 

Triple-pane windows offer even higher levels of energy efficiency, with some estimates suggesting a 30-40% reduction in energy consumption. They are effective in colder climates or for buildings with high energy demands. 

Low-E coatings applied to glass can also reflect heat back into the room during the winter and out of the room during the summer. This technology can reduce energy consumption by up to 15%.  

Privacy requirements 

For areas where privacy is important, obscured glass, frosted glass, or patterned glass can be used to diffuse light and provide a sense of seclusion. 

A more affordable alternative is to apply privacy film, which can be easily installed on the interior or exterior of windows and doors, providing various levels of opacity. Privacy films are available in a wide range of styles, including frosted, patterned, and mirrored finishes. 

Aesthetic preferences 

The appearance of your windows can significantly impact the overall aesthetic of your home or building. Consider the style and colour of your windows and how they will complement your existing décor. 

Popular window styles include casement, awning, sliding, and bay windows. 

Casement windows open outward for optimal ventilation and a traditional look. Awning windows, hinged at the top, provide ventilation while shielding from rain. Sliding windows offer a sleeker, more modern design and easy operation. Bay windows, with their angled shape, create a spacious and welcoming interior, often used in living rooms and bedrooms. 

As for window colours, white, black, and earth tones are popular. White windows offer a timeless and classic look, black windows add a modern and dramatic touch, and earth tones, such as brown, beige, and gray, create a natural and inviting feel. Custom colours are also available, which can be matched to your home’s trim or siding for a cohesive appearance. 

Budget 

The budget for windows can vary significantly based on factors such as size, materials, installation, and local market conditions. The following table provides a general estimate for a standard-sized window in Brisbane. 

Additional factors influencing price include: 

• Size, so larger windows will generally cost more. 
• Materials, such as high-quality ones, thicker glass, or premium coatings. 
• Installation can also add to the overall price. 
• Customisation, such as unique shapes, colours, or hardware. 
• Frame material, like aluminum, timber, uPVC 

Because of the significant differences in prices, it is important that you obtain quotes from multiple suppliers to compare prices and find the best deal for your specific needs. 

Selecting Window Glass Types for Your Home

Selecting the appropriate window glass types for your home or office is essential for achieving optimal natural light, energy efficiency, comfort, and overall well-being. 

By carefully considering factors such as climate, energy goals, privacy requirements, aesthetics, and budget, you can make an informed decision that will enhance your living or working space, and most importantly make you or your client feel satisfied with your choice. 

Remember, the right glass type can not only improve your home’s appearance and energy efficiency but also contribute to a more sustainable future. If you’re not sure what window glass types you want to install in your home, contact us now, we’re happy to help. 

Frequently Asked Questions 

Which type of glass is best for windows? 

The best glass type depends on your specific needs. Still, options like insulated glass, low-E glass, or laminated glass often provide a good balance of energy efficiency, safety, and comfort. 

In Australia, insulated glass is widely used due to its energy efficiency benefits, especially in colder climates like Tasmania. Laminated glass is commonly used in areas where safety is a concern, such as ground-floor windows or areas with high foot traffic. Low-E glass is becoming increasingly popular due to its ability to reduce heat transfer and improve energy efficiency. 

What is the highest quality of glass? 

High-quality glass is often characterised by its durability, energy efficiency, and safety features. Options like tempered glass and laminated glass are known for their strength and resistance to breakage. 

Tempered glass and laminated glass are both popular choices for high-quality windows in Australia. Tempered glass is particularly suitable for areas where safety is a concern, such as ground floor windows or areas with high foot traffic. Laminated glass offers both safety and sound insulation benefits, so it is a good choice for homes and businesses in noisy areas. 

What type of glass is most commonly used for windows? 

Annealed glass is a common choice for windows due to its affordability and ease of manufacturing. However, for modern homes and buildings, insulated glass and low-E glass are increasingly popular due to their energy efficiency benefits. 

What is the most common glass for windows in Australia? 

The best type of glass for windows in Australia depends on the local climate and specific needs. In tropical climates, low-E glass and tinted glass can help reduce heat gain and improve energy efficiency. 

In tropical climates like Queensland and the Northern Territory, double-pane insulated glass with low-E coatings can offer a good balance of energy efficiency and comfort. In colder climates like Tasmania and the Alpine regions, double-pane or triple-pane insulated glass with low-E coatings can help retain heat and reduce energy loss. 

Tinted glass may also be beneficial in certain areas for glare protection and reduced heat gain. 

What is the best window glass for sun protection? 

Tinted glass and low-E glass are excellent options for sun protection, as they can help reduce glare and heat gain. Laminated glass can also provide UV protection. 

Privacy films are also an effective option for sun protection, especially if you’re on a budget. It can be applied to existing windows to reduce glare, heat gain, and UV exposure. Privacy film is available in various tints and patterns, allowing you to customise the level of protection and aesthetic appeal. 

What is the best glass window to reduce heat? 

Insulated glass with low-E coatings is a top choice for reducing heat transfer in both directions. This helps keep heat inside during the winter by insulating properties of the glass, and the low-E coating helps reduce heat loss, keeping your home warmer and reducing heating costs. 

It also keeps heat out during the summer. The low-E coating reflects solar heat back outside, helping to keep your home cooler and reducing cooling costs. 

Tinted glass can also help reduce heat gain by blocking some of the sun’s heat and light. However, it’s important to note that tinted glass can also reduce natural light, so it’s best to balance the benefits of heat reduction with the desired level of natural light. 

What are the most energy-efficient window glass types? 

Insulated glass with low-E coatings is generally considered the most energy-efficient window glass types. Triple-pane glass, while not often used in Australia, can also offer even higher levels of insulation. 

Which are the more expensive window glass types? 

Insulated glass, laminated glass, and low-E glass are typically more expensive than annealed glass. However, their long-term energy savings can offset the initial cost. 

What are the cheapest window glass types? 

Annealed glass are generally the cheapest window glass types, most commonly used in Australia for residential and commercial applications where safety is less of a concern, usually for: 

• Picture frames, due to its clarity and affordability 
• Interior doors to keep the aesthetic without driving up the costs 
• Windows in older buildings or where safety is not a primary concern 
• Decorative elements such as tabletops, shelving, and partitions. 

What is the strongest window glass types for the home? 

Tempered glass and laminated glass are both known for their strength and durability. Laminated glass is particularly resistant to impact.