Shaped Sealed Units
Any non-rectangular shape — arched heads, circles, triangles, trapezoids, rakes, pentagons and complex bespoke designs. Flexible warm edge spacer for all curved sections. Same thermal and acoustic performance as rectangular units.
Shaped Units — Any Design
CSU Ltd manufactures sealed units in any non-rectangular shape using flexible warm edge spacer technology. From simple arched window heads and circular portholes to complex compound curves and one-off bespoke designs, our production handles the full range of shaped glazing. All shaped units maintain the same thermal and acoustic performance as rectangular units and use the same dual-seal system, argon gas fill and warm edge spacer options.
Available Shapes
- True Arch: Semi-circular, segmental, Gothic pointed, Tudor flat, elliptical, lancet
- Circle: Full (porthole/bullseye), half (lunette/fanlight), quarter (quadrant)
- Triangle: Right-angle, equilateral, isosceles, scalene
- Trapezoid: Angled sides — gable-end windows, dormer cheeks
- Rake: One angled edge matching roof pitch — gable/attic windows
- Pentagon / Hexagon / Octagon: Multi-sided geometric shapes
- Radius Corners: Rectangular with radiused corners
- Compound Curves: S-curves, parabolic, multi-radius
- Bespoke: Any custom shape to template or CAD
Specifications
Gas Fill — Air as Standard, Argon Optional
CSU sealed units are air-filled as standard. Argon gas fill (minimum 90% concentration) is available as an optional upgrade. Argon has 34% lower thermal conductivity than air (0.018 vs 0.026 W/mK), improving thermal insulation by approximately 15%. Argon is an inert, non-toxic, odourless gas that makes up 0.93% of Earth’s atmosphere — it is inert and environmentally neutral. Krypton gas is available by special order for slim-cavity heritage applications where maximum performance is needed in a narrow gap.
| Property | Dry Air | Argon (Optional) | Krypton (Special) |
|---|---|---|---|
| Thermal Conductivity | 0.026 W/mK | 0.018 W/mK | 0.010 W/mK |
| U-Value Benefit | Reference | ~15% better | ~25% better |
| Optimal Cavity | 12-16mm | 16-20mm | 10-12mm |
| Depletion Rate | N/A | <1% per year | <1% per year |
| Relative Cost | 1× | ~1.2× (included free) | ~50× (premium) |
Spacer Bar Options — Warm Edge vs Aluminium
The spacer bar separates glass panes and creates the sealed cavity. Traditional aluminium spacers conduct heat rapidly (160 W/mK), creating a cold thermal bridge at the unit edge that causes condensation and heat loss. Warm edge spacers use low-conductivity materials, reducing this bridge by up to 94%. CSU recommends Swisspacer Ultimate or Super Spacer TriSeal for all projects.
| Spacer | Material | Conductivity | Psi Value | Edge Temp vs Alu | Colours |
|---|---|---|---|---|---|
| Aluminium | Aluminium alloy | 160.0 W/mK | 0.080 W/mK | Baseline (cold) | Silver, White, Black, Brown, Grey |
| Swisspacer Ultimate | Composite polymer | 0.19 W/mK | 0.030 W/mK | +3-4°C warmer | Black, White, Brown, Grey, Oak +15 |
| Super Spacer TriSeal | Silicone foam | 0.17 W/mK | 0.028 W/mK | +3-4°C warmer | Black, Grey |
| Thermix TX.N Plus | Stainless + plastic | 0.60 W/mK | 0.040 W/mK | +2-3°C warmer | Silver / Black |
| TGI Spacer | Stainless + polymer | 0.90 W/mK | 0.050 W/mK | +1-2°C warmer | Silver |
Warm edge improves Uw by 0.1-0.2 W/m²K, eliminates edge condensation, and can improve WER by one full band. Available in widths: 6, 8, 10, 12, 14, 16, 18, 20, 22, 24mm.
From Template to Fitting
| Stage | What happens |
|---|---|
| Template | Your template or CAD drawing fixes the geometry — manufacture starts from this. |
| Manufacture | 5-7 days for most shaped configurations. |
| On site | Support the longest straight edge upright on padded A-frames. Protect every apex and curve — points chip first. Suckers over 25 kg, mechanical over 60 kg, lifted close to the centre of the pane. |
| Fitting | Within 28 days, above 5°C — while the opening still matches the template. |
Related Products & Glass Types
Common Questions
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