Slim aluminium casement windows with award-winning design
The Sieger Slim Casement Window is an award-winning aluminium window system designed for modern homes, extensions, replacement glazing and architectural projects where clean framing and strong performance matter.
With a 65mm sightline across the vent and frame, square-edge aluminium detailing and flexible fixed, side hung and top hung configurations, the system offers a refined window design that works across both contemporary new builds and high-end renovation projects.
Sieger Systems supplies and installs slim aluminium casement windows across London, Buckinghamshire, Berkshire, Oxfordshire, Hertfordshire, Surrey, Bath, Bristol and Somerset.
Premium performance
Bespoke made to order
Designed & made in the UK
PRODUCT FEATURES
Sieger slim casement window features
Slim 65mm sightline
A 65mm vent and frame sightline creates a clean aluminium window profile with balanced proportions.
Flexible openings
Side hung, top hung and fixed window configurations can be specified across the same system.
PAS 24 security
PAS 24 certification supports secure performance for residential and commercial projects.
Award-winning system
An award-winning aluminium window system suited to both new buildings and replacement glazing.
To learn more about additional features:
Technical performance
| Sightline | 65mm across vent and frame |
| Thermal performance | Uw values from 1.1 W/m²K |
| Maximum opening sizes | Side hung: 700mm x 1300mm | Top hung: 1200mm x 1300mm |
| Glass specification | Up to 44mm glass with double glazing, low-E coating and argon gas |
| Security | PAS 24 certified |
| Weather protection | Air Class 4, wind 2400 Pa and water E1200 |
GLASS OPTIONS
- Double glazed units
- Glass units up to 44mm thick
- Low-E coated glass
- Argon gas filled glazing
- Solar control glass
- Laminated safety glass
- Switchable tinted glass
- Heated glass
Real projects
View our products in action.
