Aluminium Windows Types, Sizes & Dimensions Guide 2025
Aluminium windows now hold 58% of the UK commercial and premium residential market (Palmer Market Research 2024). They last 45+ years, achieve U-values as low as 0.8 W/m²K with triple glazing, and allow 25-30% more daylight than uPVC due to slimmer frames (27-45 mm sightlines) aluminium windows types and sizes.
This guide gives you the exact types, standard UK sizes, maximum spans, and real-world combinations that fitters and architects actually use in 2025 – no fluff, no upsell aluminium windows types and sizes.
Why Aluminium Beats Other Materials in 2025
- Zero rot or warp – even in coastal areas with salt spray
- Powder-coated finish guaranteed 25-40 years (Qualicoat standard)
- Recyclable at 95% with no loss of quality
- Structural strength allows spans up to 3 m × 2.4 m per pane without extra bars
- Average energy saving: 38% lower heating bills vs single-glazed timber (BRE tests)
Now let’s go straight to the 8 types you will actually choose from.
The 8 Main Types of Aluminium Windows (With 2025 Specs)
- Casement (Side-Hung) Most popular type – 62% of UK installations. Opens outwards on hinges. Standard sizes: 600×900, 900×1200, 1200×1200, 1200×1500 mm Max single sash: 900 mm wide × 1500 mm high (friction stays) or 1200×1800 mm (butt hinges) Best for: bedrooms, kitchens, fire escape routes (meets 450×750 mm clear opening rule)
- Tilt & Turn One handle – tilt inwards for ventilation, turn for full opening and easy cleaning. Standard sizes: 600×1200, 800×1400, 1000×1500, 1200×2000 mm Max recommended: 1400 mm wide × 2000 mm high (weight limit ~90 kg per sash) Best for: high-rise flats and bathrooms
- Sliding Windows Horizontal sliding on rollers – zero swing space needed. Standard 2-panel: 1500×1200, 1800×1200, 2400×1500 mm Max total width: 6000 mm (4 panels) Best for: wide kitchen pass-through or patio servery
- Fixed Picture Windows Non-opening – maximum glass area. Common sizes: 1800×1200, 2400×1500, 3000×2000 mm Max single pane: 3000×2500 mm (6 mm toughened + 20 mm spacer) Best for: living rooms and stairwells
- Bi-Fold Windows (Folding Servery) Panels fold like concertina – perfect for café-style openings. Per panel width: 700–900 mm Common configs: 3 panels = 2100–2700 mm total, 5 panels = up to 4500 mm Best for: kitchen-to-garden servery bars
- Vertical Sliding Sash Traditional look with modern thermal performance. Standard box sizes: 900×1500, 1200×1800, 1400×2100 mm Max drop: 2400 mm Best for: period and conservation-area homes
- Pivot Windows Rotates horizontally or vertically – used in commercial and modern homes. Typical size: 1200×1800 mm centre pivot Best for: hard-to-reach areas above kitchens
- Tilt-Slide (Parallel Slide) Large panels slide and tilt – popular in Europe, growing in UK adoption 2024-2025. Max size: 3000 mm wide × 2400 mm high Best for: balconies and Juliet guards
Standard & Maximum Sizes Table (UK 2025)
| Type | Min Size (mm) | Common Sizes (mm) | Absolute Max (mm) | Notes |
|---|---|---|---|---|
| Casement | 400×600 | 900×1200, 1200×1500 | 2400×1800 total | Split into multiples above 1800 wide |
| Tilt & Turn | 500×800 | 1000×1500, 1200×2000 | 1400×2400 | Weight limit 90-100 kg |
| Sliding (2-panel) | 1200×900 | 1800×1200, 2400×1500 | 6000×2400 (4-panel) | Overlap 100-150 mm |
| Fixed | 600×600 | 2400×1500, 3000×2000 | 4000×3000 | Depends on glass thickness |
| Bi-Fold Window | 1400 total | 2100–3600 total | 5600 (7 panels) | 700-900 mm per panel |
| Vertical Sash | 800×1200 | 1200×1800 | 1400×2400 | Spiral balance or weight & pulley |
Source: Based on Schuco, Reynaers, Aluk and Senior Architectural Systems technical manuals 2025.
Real Prices in 2025 (Supply Only, White Finish)
- 1200×1200 casement, double glazed: £320–£420
- 2400×1200 two-panel sliding: £780–£980
- 3000 mm 4-panel bi-fold window: £1,650–£2,100
- Anthracite grey or black +£80–£150 per window
Final Tip From Someone Who Measures These Every Day
Always order 10-15 mm smaller than the structural opening in both directions. Aluminium doesn’t flex like uPVC – too tight and you crack the plaster reveal on install day.
That’s it. You now have every type, exact size and current price range used across the UK in 2025. Bookmark this page – it gets updated every January.
Need help with your exact opening? Drop the rough width × height in the comments and I’ll tell you the best type and real cost within minutes.
