Window Wall Systems
The economical glazing solution for mid-rise buildings. Hanart engineers aluminum window walls — stick-built and unitized — with thermal break, acoustic glazing and floor-to-ceiling transparency, fabricated in Shanghai and installed worldwide.
What is a window wall system?
A window wall system is an aluminum-framed glazing assembly installed between floor slabs, where every panel rests on the slab below and transfers its weight to the building structure. Unlike a curtain wall — which hangs on the building edge and spans two or more floors — a window wall is supported floor by floor. This makes it lighter, faster to build and significantly more economical on mid-rise projects below 60 m.
Chinese developers and international architects increasingly specify window walls for residential towers, hotels, offices and mixed-use podiums where the depth of the building slab and the desire for natural daylight meet a tight budget. The system delivers the same visual language as a glass curtain wall — slim sightlines, floor-to-ceiling glazing, high-performance coatings — without the structural steel sub-frame or heavy unitized crane lifts required on tall towers.
- Slab-supported construction: no continuous spandrel steel needed
- 60–120 mm sightlines with thermal-break profiles
- Integrated operable windows for natural ventilation
- Modern factory fabrication tolerance ±1.5 mm
There is no one-size-fits-all answer to window wall vs curtain wall. Hanart reviews the building height, wind zone, slab edge detail and budget before recommending the right system — and supplies both from the same factory.
Stick-built and unitized window wall
Two fabrication strategies, one performance standard. The choice depends on building height, site access and program speed.
Stick Window Wall
Mullions and transoms are installed on site, then glass and panels are glazed floor by floor. Lowest cost, fastest to start, ideal for buildings up to 30–40 m with standard repetitive floors.
- Profile sightlines 60–120 mm
- Dual-color and thermal-break options
- Glass from 24 mm insulating units
- Simple integration with local balconies and louvres
Unitized Window Wall
Pre-glazed modules — frames, glass, gaskets and insulation — assembled under factory QC and lifted into place. Fewer site trades, faster weather-tight envelope, better airtightness.
- Module widths 1.2–2.4 m
- Factory-tested gasket joints
- Watertightness Class R7–R8
- Preferred for 40–60 m buildings
Window wall performance envelope
Indicative values from Hanart-verified assemblies, confirmed per project by performance testing.
| Parameter | Standard | High-Performance |
|---|---|---|
| U-value | 1.4–1.6 W/m²·K | 0.9–1.2 W/m²·K (triple glazing) |
| SHGC | 0.35–0.50 | 0.22–0.35 |
| Visible light transmittance | 55–70% | 40–60% |
| Watertightness | Class R6 | Class R7–R8 |
| Airtightness | Class A2 | Class A3 |
| Wind load resistance | ≥ 2.0 kPa | ≥ 3.0 kPa |
| Acoustic insulation | Rw 35–38 dB | Rw 40–42 dB |
| Opening type | Casement / projected | Tilt-and-turn, motorized |
Where window walls work best
Mid-rise residential & hotels
Balconies, operable windows and per-apartment ventilation make the slab-supported window wall the natural choice. Thermal-break profiles keep hotel rooms quiet and energy-efficient.
- Floor-to-ceiling glazing up to 3.2 m
- Integrated balcony doors
- Acoustic Rw 40 dB on glazing units
Offices & mixed-use podiums
Unitized window walls deliver a fast weather-tight envelope for office floors with repetitive layouts, while allowing curtain wall glazing on the tower above — a common mixed-tower facade strategy.
- Fast vertical progress
- Clean sightlines with dual-color frames
- Stripe and vision/spandrel options
Renovation & retrofit
Window walls can be installed from inside or outside with a compact anchorage, making them the preferred system for facade renovation where access is limited and the structure must not be overloaded.
- Compact anchoring to slab edges
- Low added structural load
- Phased installation without full evacuation
Engineered for deflection, drainage and durability
Window walls sit on live structures: concrete creeps, slabs deflect and thermal movement is continuous. Hanart designs every window wall with engineered clearance, drainage paths and movement accommodation so the facade stays watertight for decades.
- Structural design for wind, seismic and thermal movement
- Three-level drainage: outer, cavity and inner seals
- Condensation risk analysis to ISO 10211
- Firestopping at slab edges to EI 60/120
- Mock-up test program before mass production
Window wall questions, answered
A window wall sits on the floor slab and supports its own weight from slab to slab, while a curtain wall hangs off the building edge and spans multiple floors. Window walls are typically more economical below 60 m; curtain walls allow uninterrupted floor-to-ceiling glass on high-rise towers. Hanart supplies both systems.
Window walls are most cost-effective on buildings up to 40-60 m. Above that height, wind load and structural movement make a unitized curtain wall the better choice. We review your building height and geometry before recommending a system.
Yes. Tilt-and-turn, casement and projected windows can be integrated into the window wall framing, with motorized actuators available for automated night-purge ventilation.
With thermal-break frames and double or triple glazing, Hanart window walls achieve U-values from 1.5 W/m²·K down to 0.9 W/m²·K, meeting passive-house floor-edge performance when combined with a properly insulated spandrel.
Yes. Hanart has delivered window wall and curtain wall projects across Southeast Asia, the Middle East, Africa and Central Asia since 2009, with dedicated fabrication, export crating and overseas installation teams.
Plan a window wall for your next building
Send your drawings and performance targets. We'll recommend the system (stick or unitized), glass specification and preliminary budget within 24 hours.