Why Specify Steel Windows

Steel has roughly three times the tensile strength of aluminum, and that structural advantage translates directly into narrower frames. HERRERO steel profiles can be as slim as 1 inch — a level of minimalism aluminum cannot reach at equivalent structural performance.

That matters when the window is supposed to disappear into the architecture: floor-to-ceiling glass walls, large pivot configurations, open-corner assemblies. See the full steel vs. aluminum comparison.

Thermal Performance and Title 24

Steel is an excellent structural material and an excellent thermal conductor — which is the problem a thermally broken window solves. In a solid steel frame, the same metal that carries the load conducts heat between inside and outside: summer solar gain in California’s hot inland zones, and condensation on cold interior frame surfaces in humid conditions.

A thermally broken window incorporates a continuous non-conductive material, typically a high-performance polyamide, inside the steel profile. It separates the interior and exterior steel and interrupts the conductive path, while keeping the narrow sightline.

Our ECO-SKY thermally broken line delivers U-factor and SHGC values that satisfy Title 24 across California’s 16 climate zones, with full compliance documentation for permit applications. Read the architect’s guide to thermal breaks or review Title 24 requirements for steel fenestration. We supply NFRC ratings and labels for submittal.

Glass

Windows are glazed to the performance the project requires: low-E, tempered, laminated, obscure and insulated units, selected against the envelope calculation rather than by default. Review glass options.

Corrosion Protection and Finishes

Every unit is hot-dip galvanized as standard — immersed in molten zinc at roughly 840°F, forming zinc-iron alloy layers bonded to the steel at the atomic level rather than a coating sitting on the surface. Most manufacturers sell this as an upgrade. How it works.

Over that substrate we apply powder coat finishes in the full RAL palette plus custom colors and textures. See finish options. With proper finishing, a HERRERO steel window is designed to last 50 to 100 years.

Specifying Steel Windows in California

• Title 24 energy compliance — determines the glazing package and whether a thermal break is required.
• WUI wildfire zones — governs assemblies in fire-prone areas.
• Coastal salt air — drives the corrosion protection and finish system.

We work directly with architects, general contractors and developers across all 16 California climate zones. Resources for architects and designers.

What We Need to Quote Your Project

An accurate estimate requires: rough opening dimensions for each unit; wall assembly type (wood frame, steel frame, masonry or concrete); glass performance requirements (standard, Title 24, WUI zone or coastal); desired finish color and type; hardware preferences; and any special conditions such as curved openings, non-standard configurations or high-elevation installations.

For projects under $20,000 we typically respond within 5–7 business days. Projects between $20,000 and $100,000 take 7–10 business days. See the full ordering timeline and approval process.