Optio 58 BW ST Steel Replacement Windows

The look of steel, the benefits of aluminium. A win-win for designers and homeowners alike.

The 58BW ST window system provides an ideal solution for the replacement of existing steel windows. The system is available in a range of styles and can be top, bottom or side hung to meet the needs of your project. The design replicates the narrow sight lines associated with steel windows whilst providing superior performance and security.

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Minimal, durable, secure.

Featuring industry leading build quality, our 58BW ST aluminium windows are an ideal replacement for existing steel windows. In addition to impressive high thermal and acoustic performance, the design also replicates the minimal sight lines associated with steel windows, whilst providing superior performance and security. Yet another win-win.

Design Features

  • 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


  • 58mm or 70mm frame depth to accommodate varying types of applications
  • Internally or externally glazed
  • Glazing 24mm – 32mm
  • Available for Lifetime Homes (LFT)
  • Available in a range of single or dual colour and anodised finishes
  • Available in the following aesthetics: Bay, Heritage and Contemporary
  • Available in the following configurations: top hung, bottom hung, side hung, fixed light, multilight and French casement


U value W/m²K (Double glazing) 1.4 W/m²K
U value W/m²K (Triple glazing) 1.2 W/m²K
Window energy rating A – B
BRE Green Guide rating A Rated
Acoustic performance (dB) Rw (C;Ctr) 43 (-2;-5) dB
Air tightness (Pa) Class 4 (600 Pa)
Water tightness (Pa) Class 9a (600 Pa)
Wind load (Pa) Class E2400 (2400 Pa)
Security PAS 24
Certifications Q-mark
Secured by design

Size Limits

Top hung (max weight) 35 Kg
Side hung (max weight) 24 Kg
Bottom hung (max weight) 60 Kg (3 hinges)
Fixed light (max weight) 250 Kg

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