Technical Specifications
Sightline (best)
2.22" (56.5 mm) - Burglarproof
U-Factor (best)
0.13 (Uw 0.74, HI+)
U-Factor (HI)
0.17 (Uw 0.99)
Max Glazing
2.56" (65 mm) - Functional
Air Infiltration
Class 4 (EN 12207)
Water Resistance
Class 9A (600 Pa)
Wind Load
Class C4 (1,600 Pa)
Max Sash Height
9' 10" (3,000 mm) - HI+
Max Sash Weight
375 lbs (170 kg)
Design Variants
Classic, Ferro, Cubic, Functional
Insulation Tiers
Standard, HI, HI+
Overview
What makes the SlimLine 38
stand out.
SlimLine 38 delivers the industrial steel-window aesthetic that architects love - with modern aluminum thermal performance. Nine configurations across four design variants (Classic, Ferro, Cubic, Functional), three insulation tiers (Standard, HI, HI+), plus fireproof and burglarproof editions. The new HI+ achieves Uw 0.74 with 100% recycled insulation bars and supports 3-meter sash heights. Ferro's sharp shadow-gap detailing replicates traditional steel windows. Glass fibre reinforced polyamide breaks (40 mm frame, 32 mm sash) deliver real thermal performance from a slim profile.
Key Highlights
- Nine configurations: 4 design variants x 3 insulation tiers + fire + security
- HI+ achieves passive-level Uw 0.74 with 100% recycled insulation bars
- Ferro: sharp shadow-gap steel-look for heritage and industrial projects
- Cubic: robust stepped profile, 76 mm depth, modern squared aesthetic
- Fireproof variant: EI2 30 / EW 30 rated (30-minute integrity)
- Burglarproof: RC2, narrowest sightline at 56.5 mm
Ideal For
Contemporary and industrial-style homes, loft conversions, heritage renovations with modern performance requirements, and interior glass partitions where the steel-look trend is key to the design intent.
Consider an Alternative When
If you need better thermal performance without giving up the slim look, the SlimLine 68 Casement offers a 0.18 U-factor with triple glazing. If you're in a cold climate zone (4+), SL38's double-pane limit may not meet your energy code.
Interested in the SlimLine 38?
Send me your window schedule and I'll price SlimLine 38 units for your project - full spec, DDP to your job site, within 48 hours.