Triple Glazed Sealed Units
Three panes, two argon cavities, dual Low-E coatings. U-values as low as 0.5 W/m²K for Passivhaus and ultra-low energy buildings. 33-50% better thermal performance than the best DGU.
CSU Standard TGU
44mm (4-16-4-16-4) with dual Pilkington Optitherm S3 on surfaces 2+5, argon fill, Swisspacer Ultimate. U-value: 0.6 W/m²K.Triple Glazed — Ultimate Performance
Triple glazed units deliver the highest thermal performance available in insulating glass. With dual Low-E coatings on surfaces 2 and 5, warm edge spacers as standard, and argon or krypton gas fill, our TGUs achieve centre-pane U-values as low as 0.5 W/m²K. TGUs are approximately 50% heavier than DGUs — a 4-16-4-16-4 TGU weighs 30 kg/m² vs 20 kg/m² for a 4-20-4 DGU. Verify frame profiles and hardware are rated for the increased weight.
Krypton gas is available for slim TGU profiles — a 4-8-4-8-4 krypton TGU at just 28mm thick achieves U-value 0.8 W/m²K, matching a standard argon DGU in a frame designed for double glazing.
Specifications
Performance Data
| Configuration | Thickness | U-Value | Rw (dB) | Light | g-value | Weight/m² |
|---|---|---|---|---|---|---|
| 4-12-4-12-4 Argon WE | 36mm | 0.8 | 33 | 72% | 0.50 | 30 kg |
| ★ 4-16-4-16-4 Argon WE | 44mm | 0.6 | 35 | 72% | 0.50 | 30 kg |
| 6-12-4-12-6 Argon WE | 40mm | 0.7 | 37 | 70% | 0.48 | 40 kg |
| 6-14-6-14-6 Argon WE | 46mm | 0.7 | 38 | 68% | 0.47 | 45 kg |
| 4-12-4-12-4 Krypton WE | 36mm | 0.6 | 33 | 72% | 0.50 | 30 kg |
| 4-8-4-8-4 Krypton WE | 28mm | 0.8 | 31 | 72% | 0.50 | 30 kg |
| 6.4L-14-4-14-6.4L Acoustic | 48.8mm | 0.7 | 42 | 66% | 0.45 | 42 kg |
TGU vs DGU Comparison
| Property | Best DGU (4-20-4 WE) | Standard TGU (4-16-4-16-4) | Improvement |
|---|---|---|---|
| U-Value | 0.9 W/m²K | 0.6 W/m²K | 33% better |
| Acoustic | 30 dB | 35 dB | +5 dB |
| Weight | 20 kg/m² | 30 kg/m² | 50% heavier |
| Thickness | 28mm | 44mm | 57% thicker |
| Internal glass temp* | 16°C | 18°C | Warmer |
Applications
- Passivhaus buildings: U-values meet Passivhaus performance targets
- Premium residential: Maximum comfort, minimal bills, no cold spots
- High noise areas: Up to 46 dB with acoustic laminated plies
- BREEAM Excellent/Outstanding: Commercial buildings targeting top ratings
- Exposed locations: Coastal, hilltop, north-facing
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.
What a Triple Weighs
Three panes instead of two puts roughly 50% more glass in the frame — the cavity widths change the thickness, not the weight:
| Unit | Weight/m² | 600×900 | 1000×1200 | 1500×2000 |
|---|---|---|---|---|
| 4-20-4 DGU (for comparison) | 20 kg/m² | 10.8 kg | 24 kg | 60 kg |
| 4-16-4-16-4 TGU | 30 kg/m² | 16.2 kg | 36 kg | 90 kg |
| 6-14-4-14-6 TGU | 40 kg/m² | 21.6 kg | 48 kg | 120 kg |
| 6-16-6-16-6 TGU | 45 kg/m² | 24.3 kg | 54 kg | 135 kg |
A patio-door-sized triple can pass 100 kg — check your exact size on the glass weight calculator before booking the fitting team.
A triple carries roughly 50% more glass than the equivalent DGU, and everything on site follows from that. Units cross the 25 kg suction-lifting threshold at modest sizes and reach the 60 kg mechanical-handling point sooner than you’d expect — check weights before delivery day, not after. Two cavity seals per unit also means double the edge to protect: pads between units, zero glass contact, upright on A-frames under cover.
The extra mass acclimatises slowly — allow more time before fitting, never below 5°C, and glaze within 28 days.
Lead time: 5-7 days standard, 3-4 days express.
Related Products & Glass Types
Get a Trade Quote
Contact our sales team — most quotes returned within 2 hours.