Optio 58BW HI Casement Window

House with AluK aluminium windows from the outside

Introducing the strong, secure and superior 58BW HI aluminium window

Versatile and energy-efficient with plentiful options for configurations and styles, this modern-day classic will transform you home.

The 58BW HI Casement window system is built to the highest UK standards, ensuring the highest levels of safety and performance to keep your home warm and secure.

The clean lines of this highly popular casement window range can be further enhanced with four different aesthetics to suit your property:

  • Ovolo – a slim and stylish stepped edge
  • Chamfered – a traditional design that compliments heritage style properties
  • Square – a modern and minimal flat sash for contemporary designs
  • Flush – slim sightlines and the popular flush aesthetic

With a range of customisable options, including slim and standard frame depths, the 58BW HI window is the perfect choice for both traditional and contemporary residential designs.


  • Certified under the Secured By Design scheme
  • Tested to PAS 24
  • Green guide rated A
  • Integrated deep head profiles for ease of trickle ventilation
  • Unique polyamide thermal break design to improve thermal performance


  • Glazing 24mm – 40mm
  • Internally or externally glazed
  • 58mm or 70mm frame depth to accommodate varying types of applications
  • Project in or project out options
  • Available in a range of single or dual colour and anodised finishes
  • Available in the following aesthetics: Flush, Bay, Chamfered, Heritage, Ovolo and contemporary
  • Available in the following configurations: top hung, bottom hung, side hung, fixed light, multi-light and French casement
  • Available for Lifetime Homes (LFT)


The 58BW Casement range is a tried and trusted window system that delivers exceptional performance, functionality and safety.

Low U-values of 1.2 for triple glazing and 1.4 for double glazing, and a Green Guide ‘A’ Rating, make this energy efficient window the ideal partner for both new build and refurbishment projects where warmth and comfort are paramount.

With impressive air, water and wind resistance test figures, this system can withstand extreme weather conditions, keeping your home warm and dry.

Safe and extremely secure, this window system is certified under the Secured by Design scheme, and tested to PAS 24, which means it has been rigorously tested.

The 58BW Casement range is available in several configurations to suit your project: top hung, side hung, bottom hung, fixed light, multi-light and French casement. It is also available in two frame depths to suit the thickness of your walls: 58mm and 70mm.

As with all AluK aluminium systems, the 58BW Casement is available in single or dual colour powder coating, texture and anodised finishes.

Standard Technical Data HI technical data
U value W/m²K 1.2-1.5 W/m²K 1.2-1.4 W/m²K
Window energy rating B-C B-C
Air tightness (Pa) Class 4 (600 Pa) Class 4 (600 Pa)
Water tightness (Pa) Class 9A (600 Pa) Class 9A (600 Pa)
Wind load (Pa) Class E2400 (2400 Pa) Class E2400 (2400 Pa)