At Optimum Window, we manufacture the RTS-430, RTS-430+ and RTS-430i as distinct thermally broken stainless steel window and door systems. All three are designed around a common goal: combining delicate steel sight lines with modern performance.
The right system depends on the architectural application, glazing requirements and environmental conditions.
RTS-430: Thermally Broken Steel for Architectural Applications
Our RTS-430 combines thermally broken stainless steel construction with thin sight lines and energy-efficient performance. The system is NFRC certified and has been independently tested for air, water and structural performance.
The RTS-430 accommodates dual glazing up to 1 inch and offers both Simulated Divided Lite (SDL) and True Divided Lite (TDL) muntin configurations.
Its available configurations include fixed windows, casements, French casements, doors, French doors, hoppers and awnings.
Best suited for: architectural applications where thin steel profiles, thermal performance and broad configuration flexibility are priorities.
RTS-430+: Greater Glazing Capacity With Delicate Sight Lines
Our RTS-430+ continues the same thermally broken stainless steel approach while supporting additional glazing capacity.
The system accommodates dual glazing up to 1 1/2 inches, along with SDL and TDL muntin options.
RTS-430+ has also undergone NFRC thermal performance testing, including U-factor, Solar Heat Gain Coefficient, Visible Transmittance and Condensation Resistance measurements. Performance varies according to the glass selected.
Like the RTS-430, it is available across a wide range of fixed, operable and door configurations.
Best suited for: projects that require the architectural character of thermally broken steel with greater insulated-glass flexibility.
RTS-430i: Impact-Rated Steel for Coastal Applications
Our RTS-430i was developed specifically for coastal and hurricane-impact applications. The system is designed to meet HVHZ requirements while maintaining the thin sight lines associated with architectural steel.
RTS-430i uses 304 stainless steel and can accommodate insulated glass up to 1 1/2 inches. Glazing options include laminated and dual-glazed configurations, along with SDL and TDL muntins.
The system meets NFRC ratings and Wind Zone 4 requirements.
Best suited for: coastal projects where impact resistance, wind performance, thermal efficiency and refined steel aesthetics must work together.
RTS-430, RTS-430+ and RTS-430i at a Glance
| System | Primary Application | Glazing Capability | Key Distinction |
|---|---|---|---|
| RTS-430 | Architectural residential, commercial and landmark applications | Dual glazed up to 1″ | Thermally broken stainless steel with delicate sight lines |
| RTS-430+ | High-performance architectural applications | Dual glazed up to 1 1/2″ | Expanded glazing capability with thermally broken steel construction |
| RTS-430i | Coastal and hurricane-impact applications | Laminated and dual glazing up to 1 1/2″ | Hurricane-impact rated and designed for HVHZ conditions |
Choosing the System Around the Project
We do not begin with a product name. We begin with the project.
Climate, wind requirements, glazing, opening configuration, architectural proportions and performance criteria all influence the appropriate system. Every unit is custom-made to project specifications and approved shop drawings, allowing us to coordinate engineering requirements with the architect’s design intent.
The goal is not simply to specify a steel window. It is to select the steel window system engineered for the application.
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