The Schüco AWS 75 is the standard-bearer of the mid-market aluminium window range. It's what a competent architect specifies for a residential window on a mainstream Hertfordshire project — and what a competent fabricator recommends when the client isn't chasing Passivhaus.
Frame depth and construction
AWS 75 uses a 75mm-deep aluminium profile with a polyamide thermal break. The polyamide bar isn't decorative — it's a structural component that separates the outer aluminium from the inner aluminium and eliminates the direct thermal path through the frame. That's the reason a modern aluminium window doesn't feel cold to the touch on the inside face.
Opening styles
The AWS 75 supports the standard residential range:
- Casement — side-hung and top-hung sashes, the workhorse configuration.
- Tilt-and-turn — inward opening for cleaning, inward tilt for ventilation. Common in continental European specifications, growing in UK popularity.
- Fixed light — non-opening. Cheapest per m² and thermally best.
- Reversible — a specialist configuration for high-level windows that need internal cleaning access.
Sightlines
Frame face width on the AWS 75 is 117mm for a fixed light and around 126mm for an opening sash. Meeting sightline (where a fixed and opening light share a mullion) is approximately 140mm. Those are honest numbers for a mid-market aluminium residential window. The higher AWS 90.SI+ is slimmer where sightlines matter architecturally.
Thermal performance
With double glazing:
- Uf (frame): approximately 1.8 W/m²K.
- Uw (whole window, reference size): approximately 1.3 W/m²K.
With triple glazing:
- Uw: down to approximately 0.9 W/m²K.
These figures clear Approved Document L 2021 requirements for both new-build and replacement windows in England.
Security
PAS 24 : 2016 is standard across the AWS 75 range. Where required, Secured by Design certification is available. Multi-point locking is included on all opening lights, with mushroom-cam locking points that engage into the frame — the industry-standard specification.
Where the AWS 75 fits — and where it doesn't
Specify the AWS 75 for:
- Standard residential windows on mainstream builds and renovations.
- Rear extensions where the primary glass is a bifold or slider, and the flanking windows just need to be well-specified.
- Replacement window projects where existing openings are being retained.
Consider the AWS 90.SI+ instead for:
- Passivhaus and near-Passivhaus specifications.
- Very large fixed lights where the slimmer sightline matters architecturally.
- High-exposure locations where enhanced weather ratings pay off.
Colour, finish and detailing
Standard RAL powder-coated finishes are included. Dual-colour finishes (different colour outside/inside) add approximately 15% to the frame cost. Textured and matte finishes are available at similar upcharges. Marine-grade coatings for coastal applications are a specifiable option.
Cost expectations
Installed cost for AWS 75 residential windows in the UK, per opening, ex-VAT:
| Window type | Approximate installed |
|---|---|
| Small fixed light (~0.8m²) | £450 – £700 |
| Medium casement (~1.5m²) | £900 – £1,400 |
| Large tilt-and-turn (~2.5m²) | £1,600 – £2,400 |
Sourcing near St Albans
The AWS 75 is stocked and installed by Schüco-authorised fabricators across the Hertfordshire area. 5EC's aluminium window range covers the AWS 75 alongside comparable systems from other manufacturers, with local coverage across St Albans and surrounding areas.
For manufacturer data, Schüco UK's residential windows page publishes the full AWS 75 technical dossier.
Editorial verdict
The AWS 75 is the aluminium window we'd specify by default for a mainstream residential project. It delivers on every performance requirement without over-engineering, and the price-to-performance ratio is honest.