What Types of Glass Are Used in Curtain Walls?

Glass is one of the most visible components of a curtain wall, but choosing the right glazing involves more than appearance. The glass must meet the project's requirements for thermal performance, solar control, safety, daylight, and weather exposure.

Common curtain wall glass types include insulated glazing units (IGUs), tempered glass, laminated glass, Low-E glass, and spandrel glass.

For architects, developers, and facade contractors, understanding how these glass types work helps prevent specification conflicts and unnecessary costs.

This guide explains the main curtain wall glazing options, their advantages, and the factors to consider before ordering.

What Types of Glass Are Used in Curtain Walls?

Curtain wall systems commonly use several types of architectural glass, selected according to their function within the building envelope.

The main options include:

• Insulated glazing units (IGUs): Multiple glass panes separated by a sealed cavity to reduce heat transfer.
• Tempered glass: Heat-treated glass with increased mechanical strength and a characteristic break pattern.
• Laminated glass: Multiple glass panes bonded with an interlayer that helps retain fragments after breakage.
• Low-E glass: Glass with a low-emissivity coating designed to control radiative heat transfer.
• Spandrel glass: Opaque glazing used to conceal floor slabs, columns, and building services.

These categories can overlap. Tempered or laminated glass can be incorporated into an insulated glazing unit, and Low-E coatings can be applied to suitable glass used in a multi-pane assembly.

1. Insulated Glazing Units (IGUs) for Curtain Walls

An insulated glazing unit, also called an IGU or insulated glass unit, consists of two or more glass panes separated by a sealed cavity. The cavity typically contains air or an insulating gas such as argon, while spacers and edge seals help maintain the unit's integrity.

Insulated glazing units are widely used in modern curtain walls because they help control heat transfer through large glazed building envelopes.

How Does Insulated Glazing Work?

The cavity between the glass panes reduces heat transfer compared with a comparable single-pane assembly. Low-E coatings and gas filling can further improve thermal performance, depending on the glass configuration.

For buildings with extensive glazing, the specification of the IGU affects heating and cooling demand, indoor comfort, and the risk of condensation.

PRANCE offers photovoltaic glass solar panels configurations such as 6+9A+6, 6+12A+6, and 8+12A+8. These examples show how two glass panes and an air cavity are combined into one unit, but the final configuration should follow the project’s thermal, acoustic, structural, and code requirements.

PRANCE’ s the different types of glass used in curtain wall systems clearly demonstrates how these glass options work together.

Double Glazing vs. Triple Glazing

Triple glazing is not automatically the best choice for every curtain wall. Its suitability depends on climate, energy targets, structural capacity, solar exposure, and the overall facade design.

For additional product context, see PRANCE curtain wall systems and its available facade configurations.

2.Tempered Glass Used in Curtain Walls

Tempered glass, also called toughened glass, is heat-treated to increase its strength. If it breaks, it fractures into small pieces rather than large sharp shards, which is why it is widely used as safety glazing.

PRANCE offers single tempered glass in thicknesses such as 8 mm, 10 mm, 12 mm, and 15 mm. It is suitable where transparency, impact resistance, and cost-effectiveness are important, such as commercial curtain walls, skylights, and sunrooms.

Tempered glass is strong, but it should not be treated as a complete solution for every facade. Large panels, high wind loads, acoustic needs, or post-breakage retention requirements may call for laminated or insulated glass instead.

3. Laminated Glass Used in Curtain Walls

Laminated glass consists of two or more glass panes bonded together with a polymer interlayer.

If the glass breaks, the interlayer helps hold fragments together. This property makes laminated glass useful for projects that require additional protection against falling glass, impact hazards, or certain security risks.

What Are the Benefits of Laminated Glass?

Laminated glass can provide several benefits depending on its construction:

• Fragment retention: The interlayer helps retain broken glass fragments.
• Acoustic control: Suitable laminated constructions can improve sound insulation.
• UV protection: Certain interlayers can reduce transmission of ultraviolet radiation.
• Security performance: Specially designed constructions can provide additional resistance to specified impact or intrusion risks.

These benefits depend on the glass plies, interlayer material and thickness, and the complete glazing assembly.

4. Low-E Glass for Energy-Efficient Curtain Walls

Low-emissivity glass has a specialized coating designed to reduce radiative heat transfer while allowing a selected amount of visible light to pass through.

It is often used in insulated glazing units for office buildings, hotels, residential towers, and other projects with substantial glazed facades.

What Is the Difference Between Low-E Glass and Reflective Glass?

Low-E glass is defined by its low-emissivity coating and thermal-control function. Reflective glass is generally selected for its solar-control characteristics and reflective appearance.

Some products combine low-emissivity and solar-control properties. The selection should therefore be based on verified U-factor, solar heat gain coefficient (SHGC), visible transmittance (VT), and appearance requirements rather than the coating name alone.

For performance-rating information, reference for the National Fenestration Rating Council .

5. Spandrel Glass for Curtain Walls

Spandrel glass is designed to be opaque or substantially obscure vision. It is commonly used in curtain wall areas between transparent vision-glass panels to conceal floor slabs, columns, insulation, and mechanical services.

Its primary purpose is to provide a consistent exterior appearance across both transparent and non-transparent sections of a facade.

What Should Developers Consider When Selecting Spandrel Glass?

Spandrel glass can absorb substantial solar energy because it is designed to limit light transmission. As a result, thermal stress and the conditions behind the glass need careful evaluation.

The design should account for heat treatment, coating compatibility, insulation placement, ventilation where required, and the temperatures that may develop within the spandrel cavity.

It is also important to verify the fire performance. Fire performance must be established through the appropriate system design and code requirements.

For further information, see Vitro Architectural Glass's spandrel glass guidance.

How to Choose Quality Curtain Wall Glass？

Start with the building’s performance brief. Define the required U-factor, SHGC, visible light transmission, acoustic rating, wind load, safety glazing requirements, and maintenance expectations.

Then match the glass to the climate and orientation. Cold climates often prioritize lower U-factor and reduced heat loss, while hot or sunny climates may prioritize lower SHGC, glare control, and shading.

Finally, confirm the complete assembly. PRANCE’s glass curtain wall system selection guide explains how to balance thermal performance, acoustic comfort, structural movement, budget, and long-term maintenance.

Real Curtain Wall Glass Project Example

PRANCE’ s Xiong’an Sports Center glass curtain wall project shows how custom glass panels can be used for a curved facade. The project used 3D laser scanning to capture the building geometry and support custom curtain wall fabrication.

This example is useful for projects with complex geometry, large glass areas, or special daylighting requirements. It shows that glass selection must be coordinated with panel dimensions, framing, installation drawings, and site conditions.

Curtain Wall Glass Maintenance

Glass should be inspected regularly for cracks, coating damage, sealant failure, water stains, and frame corrosion. Maintenance should also cover gaskets, drainage paths, and anchors, not only the visible glass surface.

PRANCE’s glass curtain wall maintenance and safety guide recommends routine perimeter inspections and documentation of early warning signs. It also highlights sealant and gasket care because these components protect the more expensive glass and framing system.

Curtain Wall Glass Specification Checklist for Procurement

Before ordering glass for a curtain wall, developers and procurement teams should confirm the following information with the facade consultant and supplier.

This checklist helps prevent a common procurement problem: ordering glass based on a broad product description without confirming the complete configuration and required performance.

Conclusion

For most commercial projects, the best solution is not simply one type of glass but a carefully specified combination of glass panes, coatings, cavities, framing, and seals.

PRANCE's curtain wall systems provide a starting point for evaluating facade configurations. Before procurement, confirm the complete glazing build-up, verified performance data, applicable safety requirements, and compatibility with the selected curtain wall system.

FAQs

1. What types of glass are used in curtain walls?

Common types include tempered glass, laminated glass, insulated glazing units, Low-E glass, reflective glass, tinted glass, and spandrel glass.

2. What is an insulated glazing unit?

An insulated glazing unit, or IGU, uses two or more glass panes separated by a sealed cavity. The cavity may contain air, argon, or krypton gas to reduce heat transfer.

3. Is tempered glass safe for curtain walls?

Yes. Tempered glass is a common safety glazing option because it breaks into small pieces. For areas needing post-breakage retention, laminated glass may be more suitable.

4. What is Low-E glass?

Low-E glass has a low-emissivity coating that controls radiant heat transfer. It helps reduce heat loss and solar heat gain while allowing daylight into the building.

5. Which glass is best for a curtain wall?

There is no single best glass. The best option depends on climate, orientation, safety requirements, acoustic needs, wind load, and energy targets.