What's the difference between a window wall and a curtain wall?

2025,09,02

The Core Difference Between Window Walls and Curtain Walls

The essential differences between window walls and curtain walls lie in their structural load-bearing systems and spatial positioning.

Window walls are rigidly connected to building openings via a perimeter frame, distributing loads to the main structure through linear force transmission. They are typically embedded within the wall outline and are an extension of the traditional building envelope system.

Curtain walls, on the other hand, transmit loads through point-by-point connections via anchor supports. Their structure is independent of the main frame, often projecting beyond the building's exterior contours to form a monolithic facade, offering greater spatial expression. For example, the renovation of the Western Han Dynasty Museum of the Nanyue King in Guangzhou employed a black, hollow, Low-E glass curtain wall in its hopper-shaped mound. This not only provides sunshade and visibility, but also integrates into the overall building through ventilation, demonstrating the unique advantages of curtain walls in spatial shaping.

Curtain Wall Material Selection System

Curtain wall materials must meet a comprehensive balance of mechanical properties, weather resistance, and aesthetic requirements. Glass curtain walls are primarily composed of monolithic glass, insulating glass, and laminated glass. Insulating glass, filled with inert gas, achieves excellent thermal insulation and is widely used in energy-saving retrofits for commercial buildings.

Among metal curtain walls, aluminum panels dominate due to their lightweight (density 2.7g/cm³) and high strength. Their fluorocarbon spray coating provides over 15 years of weather resistance, making them the preferred exterior finish for high-quality residential buildings. When using natural granite for stone curtain walls, back-bolted connections are required to address deadweight concerns. The weight of a single slab must be kept below 150kg to ensure structural safety. Among composite curtain walls, aluminum honeycomb panels, with their composite structure of 0.5mm aluminum face sheets and 25mm honeycomb cores, achieve half the weight while maintaining flatness, making them particularly suitable for projects with curved and irregular surfaces.

Curtain Wall Application Scenarios

Curtain wall applications show distinct differentiation. In the commercial building sector, curtain wall applications are expected to account for 69% of total applications in 2023. Super-high-rise buildings such as skyscrapers: Using a unitized glass curtain wall system, standardized modular production reduces construction time by 40%.

Public buildings: Double-skin curtain walls are used in nearly 30% of venues like hospitals and museums. Their adjustable ventilation cavity design has helped reduce annual energy consumption at the Beijing Daxing Airport terminal by 18%.

Residential sector: Although less widely used, high-end projects such as Shenzhen Bay One achieve building airtightness levels of up to 8 national standards through the combination of aluminum curtain walls and system windows, effectively addressing wind pressure leakage issues in high-rise residential buildings.

Curtain Wall Material Selection Decision Framework

The material selection process requires a multi-dimensional evaluation system:

Physical Performance

Buildings in coastal areas must select curtain wall systems with a wind pressure resistance of 3.5 kPa or higher, corresponding to a glass thickness of 12 mm or higher. Regarding weather resistance requirements, curtain wall seals must pass a 1500-hour accelerated aging test to ensure they maintain elasticity over a temperature range of -40°C to 80°C.

Economic considerations indicate that while the unit cost of concealed-frame glass curtain walls is 25% higher than that of exposed-frame systems, the 15% increase in light transmittance can generate long-term energy savings. Construction feasibility assessments must focus on material processing accuracy. The installation tolerance of point-supported curtain wall claws must be controlled within ±0.5 mm, otherwise the overall load balance will be affected.

The Core Value of Customized Curtain Walls

Customized curtain walls achieve both functional and aesthetic breakthroughs through parametric design.

In the Hangzhou Asian Games Esports Center project, designers used a parametric algorithm to generate a gradient diamond-shaped Aluminum Curtain Wall. Using BIM technology to optimize the joint structure, they achieved an installation tolerance of ±1 mm for 23,000 custom-shaped panels.

The customized development of photovoltaic curtain walls demonstrates further technological sophistication. BIPV curtain wall products achieve a photovoltaic conversion efficiency of 21.3%, generating 156 kWh of electricity per square meter annually, providing sustainable energy support for buildings. This customization transforms curtain walls from a simple enclosure into an intelligent building envelope. In the Tencent headquarters building project in Shenzhen, the double-skin curtain wall system integrates temperature and humidity sensors and motorized sunshades. Using AI algorithms, it achieves adaptive environmental control, improving indoor comfort by 30% while reducing air conditioning energy consumption by 22%.

Author:

Ms. Rebecca Lee

E-mail:

sale01@wddoorwins.com

Phone/WhatsApp:

+86 13502225784