Windows · 3 min read
Fixed Glass Windows: When Non-Openable Glazing Is the Right Choice
Fixed glass windows maximise the glazed area per frame and simplify the building facade. Here's when they are the right specification choice.
Fixed glass windows — non-openable glazed panels within an aluminium or UPVC frame — are the simplest and in many respects the highest-performing window type available. Without the hinges, stays, handles, and seals required for an openable sash, the fixed window delivers a larger glazed area per frame, a more weather-tight envelope, and a cleaner architectural profile.
When Fixed Glass Is the Right Choice
Fixed glazing is appropriate wherever ventilation is provided by other means:
- **Air-conditioned commercial buildings** — where mechanical ventilation and air conditioning (MVAC) systems handle all fresh air exchange. Fixed glazing maximises the thermal envelope performance and eliminates any risk of occupants bypassing the MVAC system.
- **Curtain wall and facade elements** — large panel sizes that are structurally inappropriate for openable sashes belong in a fixed frame.
- **High-level windows** — above 3 m from finished floor level, where safe operation is impossible without specialist equipment.
- **Acoustic walls** — where continuous weather sealing with no mechanical components maximises sound attenuation.
Glazing Options for Fixed Windows
The fixed window frame can accept any glazing specification:
| Glazing | Application |
|---|---|
| Single 6mm toughened | Low-budget, mild climate |
| DGU 4+12+4 | Standard commercial, U ≈ 2.8 W/m²K |
| DGU low-e 4+12+4 | Energy-efficient commercial, U ≈ 1.4 W/m²K |
| Triple glazed | Premium cold-climate or acoustic |
| Laminated safety glass | Ground floor, overhead, or high-risk areas |
Maximum Panel Sizes
Aluminium fixed frames can accommodate significantly larger panel sizes than openable equivalents:
- Max width: up to 3600 mm per panel
- Max height: up to 4000 mm
- Structural silicone bonding (structural glazing) can eliminate the frame from the external face entirely
Thermal and Acoustic Performance
A well-specified DGU fixed window with thermally broken aluminium frame achieves:
- U-value: down to 1.1 W/m²K
- Acoustic rating: up to Rw 42 dB
- Air infiltration: Class 4 (virtually zero)
Metanoia Global Solutions supplies aluminium and UPVC fixed glass window systems in all standard and bespoke sizes, with full thermal and acoustic performance documentation.