Double glazed windows are essential components of building in the UK, impacting energy efficiency, security, and aesthetics. The choice of glass for windows can significantly influence these factors, making it crucial to understand the available options. Over time, window glass has evolved from basic single-pane designs to advanced, multi-layered solutions that meet contemporary needs, such as energy conservation and noise reduction. Here’s a simple breakdown of the main types:
Key Points
- There are several types of glass for windows and doors, each with unique properties for safety, energy efficiency, and privacy.
- Our Research suggests that in the UK common types of glass for windows include clear (annealed), tempered, laminated, insulated, low-E, tinted, frosted, and acoustic glass.
- The evidence leans toward choosing glass based on your home’s needs, such as noise reduction or energy savings, with no single “best” type.
Different Types of Glass for Single and Double Glazing Windows
Based on the Durajoin team’s expertise in various glass types for aluminium windows and doors, we categorise different types of glass into basic, safety, energy-efficient, and specialty options. Each category serves distinct purposes, and the choice depends on factors such as climate, location, and budget.
Standard Glass Types: Basic Glass
Float Glass:
This is the basic type of glass, created by floating molten glass on molten tin to achieve a smooth, uniform surface. While it is low-cost, it is also fragile and often breaks into large, dangerous shards, making it unsuitable for use in windows without additional treatment.
Annealed Glass:
This type is derived from float glass and is gradually cooled to reduce internal stresses, making it less likely to crack. It is the standard glass used in many windows and doors, which offers maximum light transmission but falls short in terms of energy efficiency and safety. Although it is affordable and easy to maintain, its fragility can be a concern, especially in high-impact areas. These types of glass are often seen in old properties.
Safety Glass Options
Tempered Glass:
Also known as toughened glass, tempered glass is made from annealed glass that has been heated to over 600°C and then rapidly cooled. This process makes it up to five times stronger than standard annealed glass. When broken, tempered glass shatters into small, blunt pieces, which reduces the risk of injury. It is ideal for use in windows located near ground level, in bathrooms, or in high-traffic areas where safety is crucial. However, once tempered, the windows glass cannot be cut or altered, which can limit customisation, and it is typically more expensive than annealed glass.
Laminated Safety Glass:
Laminated glass consists of two or more layers of glass that are bonded together with a plastic interlayer, usually made of polyvinyl butyral (PVB). When laminated safety glass breaks, the layers hold together, minimizing the risk of injury and enhancing security. Laminated glass windows and doors is also great and effective at reducing noise, making it suitable for noise-sensitive environments, such as homes near golf courses or busy streets. This type of glass is commonly used in car windshields, hurricane windows and doors, and other security applications, although it is heavier and more costly than single-pane options.
Energy-Efficient Glass
Insulated Glass:
Commonly known as double-glazed or triple-glazed, insulated glass consists of multiple panes (typically two or three) separated by a space filled with air, argon, or krypton gas. This design significantly improves thermal performance by reducing heat transfer, making it a standard choice for energy-efficient windows. It also helps prevent internal condensation, enhancing overall comfort. This glass type is a standard requirement in the UK. However, insulated glass is generally more expensive than single-pane glass and tends to be heavier, necessitating stronger frames.
Low E Glass:
Low-emissivity (Low-E) glass features a microscopically thin metal coating, often made of silver, that reflects radiant heat. This coating helps retain heat indoors during winter while keeping heat out during summer, thereby improving energy efficiency. Additionally, Low-E glass windows blocks UV rays, protecting interior furnishings from fading. It is especially beneficial for west- and south-facing windows and can be combined with insulated glass for enhanced performance. The coating is hundreds of times thinner than a human hair, making it only slightly noticeable as a tint, but it comes at a higher cost.
Specialty Glass for Specific Needs
Tinted Glass:
This type of glass has colour added during manufacturing to reduce light and heat transmission. Available in various shades, tinted glass windows is effective for controlling glare and minimizing solar heat gain, making it ideal for sunny climates where it helps reduce cooling costs. It also enhances privacy, serving as an upgrade over obscure glass in some cases. However, it may reduce natural light, which could affect the brightness of interiors.
Frosted Glass:
Also known as obscure glass, frosted glass features a textured or patterned surface that obscures visibility while allowing light to pass through. It is commonly used in bathrooms windows, bedrooms windows, and front doors to provide privacy without the need for blinds. Options include acid-etched (frosted) or textured designs that vary in opacity. While it offers aesthetic appeal, frosted glass may not be suitable for areas that require clear views.
Acoustic Glass:
Acoustic glass is designed to reduce noise transmission. It often uses varying thicknesses and a PVB (polyvinyl butyral) layer to disrupt sound waves, reducing noise by up to 40 dB. This makes it ideal for windows located near roads, airports, or busy urban areas. Acoustic glass may also include argon gas and larger internal gaps for enhanced performance. However, it tends to be more expensive and may require specific installation, adding to overall costs.
Solar Control Glass:
This type of glass features a metallic coating that reflects infrared radiation, helping to reduce solar heat gain while allowing UV light to pass through. With a low G-value (as low as 0.17), it lets in only 17% of the sun’s thermal energy, making it energy-efficient for south or southwest-facing windows. Not all manufacturers offer solar control glass, but it plays a crucial role in preventing overheating in sunny regions.
Mirrored Glass:
Although less common for exterior windows and doors, mirrored glass has a metal coating on one side, sealed with a protective layer, creating a reflective effect. It is primarily decorative and is often used for walls or furniture rather than standard window applications due to its limited visibility.
Wired Glass:
This glass contains wires that hold it together under heat, making it fire-resistant. While it is not commonly used in residential settings, wired glass is found in schools, hospitals, and commercial properties for fire safety. It is not suitable for security applications, as it can be cut, and is less relevant for typical home windows.
Comparative Analysis for Various Types of Glass for Double Glazed Windows
To help in decision-making, here’s a table summarizing the key types, their properties, and typical uses:
| Type of Glass | Description | Key Benefits | Typical Uses | Cost Consideration |
|---|---|---|---|---|
| Annealed Glass | Slowly cooled float glass, standard clear glass. | Affordable, maximum light transmission. | Basic windows, historical replication. | Low |
| Tempered Glass | Heated and rapidly cooled for strength, breaks safely. | Increased safety, durability. | Low windows, bathrooms, high-traffic areas. | Medium |
| Laminated Glass | Layers bonded with plastic, holds together when broken. | Security, sound insulation, UV protection. | Security windows, noise-sensitive areas. | High |
| Insulated Glass | Multiple panes with air/gas, improves thermal performance. | Energy efficiency, reduces condensation. | Modern homes, energy-saving focus. | Medium to High |
| Low-E Glass | Coated to reflect heat, blocks UV rays. | Energy efficiency, protects furnishings. | Climate extremes, west/south-facing windows. | Medium |
| Tinted Glass | Coloured to reduce light/heat, enhances privacy. | Controls glare, reduces cooling costs. | Sunny climates, privacy needs. | Medium |
| Frosted Glass | Textured for privacy, allows light. | Privacy, aesthetic appeal. | Bathrooms, bedrooms, front doors. | Medium |
| Acoustic Glass | Designed to reduce noise, uses multiple layers. | Noise reduction, up to 40dB. | Near roads, airports, urban areas. | High |
| Solar Control Glass | Metallic coating reduces solar heat gain, low G-value. | Prevents overheating, energy-efficient. | South/southwest-facing windows. | Medium to High |
Practical Considerations to Choose Right Glass for Double Windows and Doors
When selecting glass for your windows, consider factors such as the direction your windows face, the local climate, noise levels, and security needs. For instance, south-facing windows may benefit from solar control or low-E glass to help manage heat. Tinted and obscure glass is best types of window glass for privacy. In urban settings, you might prioritize acoustic glass to reduce noise.
It’s also crucial to check building regulations, particularly regarding safety glass for ground-level windows or patio doors, as these may require tempered or laminated glass. Obscure glass is best types of window glass for privacy.
If you have specific needs, consult with Durajoin’s professional team for assistance in making the best decisions.
Conclusion
The various types of glass used for windows cater to the diverse needs of homeowners and builders. Ranging from basic annealed glass, which is cost-effective, to advanced acoustic glass designed for noise reduction, each type presents distinct benefits. By understanding these options, you can customize your window selections to improve safety, efficiency, and comfort, ensuring that your home achieves both functional and aesthetic objectives.
