Seamless welded joinery, slim sash profiles, and scalable performance across four Narrow Line tiers.
The Narrow Line family is Synergy Windows & Doors’ welded aluminum fenestration system, engineered to combine narrow sightlines with fully welded frame and sash assemblies. Across the family, the construction approach remains consistent: controlled sash profiles and uninterrupted perimeter weather sealing. The four tiers allow the system to be matched to the scale, glazing requirements, material direction, and architectural character of the project.
- Fully welded frame and sash assemblies
- Available as casement and awning configurations
- Side-mounted casement available in Tiers II, III, and IV
- Wood interior with aluminum or specialty metal cladding options
- All-aluminum option available in Tier IV
Narrow Line was developed as a family of welded aluminum fenestration systems rather than a single fixed product. Each tier uses the same core construction philosophy: welded frame and sash assemblies, consistent narrow sightlines, and controlled perimeter detailing. The tier structure allows the system to scale from compact wood-aluminum applications through larger glazing conditions, heritage replication work, and fully all-aluminum construction.
One Family, Four Tier Options
Tier I – LE
Original Narrow Line system for dual-insulated glazing and controlled opening sizes.
Tier II – XL
Expanded Narrow Line system for increased scale, larger sash dimensions, and higher glazing capacity.
Tier III – Heritage XL
Heritage-driven Narrow Line system for traditional proportions, replicated SDL profiles, and larger openings.
Tier IV – All-Aluminum XL
All-aluminum Narrow Line system for increased scale, replication capability, and all-metal applications.
A defining feature of the Narrow Line family is the use of welded frame and sash assemblies. This construction approach supports seamless corner execution, dimensional stability, and clean architectural sightlines across the full product family. The result is a narrow-profile system that can be tailored to different project requirements without losing the visual continuity of the Narrow Line design language.
Choose by Application
| Project condition | Recommended tier | Best Fit |
| Controlled opening sizes | Narrow Line Tier I – LE | Best fit where compact geometry, dual-insulated glazing, and defined opening sizes are required. |
| Larger wood-aluminum applications | Narrow Line Tier II – XL | Best fit where increased sash dimensions, triple-insulated glazing, laminated glass, and greater scale are required. |
| Heritage and replication work | Narrow Line Tier III – Heritage XL | Best fit where traditional proportions, custom Simulated Divided Lites (SDL), visual depth, and larger openings are required. |
| All-aluminum applications | Narrow Line Tier IV – All-Aluminum XL | Best fit where the project requires all-aluminum construction, increased scale, and replication capability. |
Narrow Line Tier Comparison
| Feature | Tier I | Tier II | Tier III | Tier IV |
| Seamless welded joinery | Yes | Yes | Yes | Yes |
| Alternative metal cladding | Yes | Yes | Yes | |
| Available as casement and awning | Yes | Yes | Yes | Yes |
| Dual-insulated glazing | Yes | Yes | Yes | Yes |
| Triple-insulated glazing | Yes | Yes | Yes | |
| Laminated glass | Yes | Yes | Yes | |
| Side-mounted casement configuration | Yes | Yes | Yes | |
| All-aluminum construction | Yes | |||
| Putty SDL style | Yes | Yes | ||
| Custom painted hardware | Yes | Yes | Yes | Yes |
Evolution of the Narrow Line Family
Narrow Line Tier I – LE
Original Narrow Line system developed for dual-insulated glazing
and controlled opening sizes.
Narrow Line Tier II – XL
Expanded for increased scale, larger sash dimensions,
and higher glazing capacity.
Narrow Line Tier III – Heritage XL
Developed for heritage-driven applications, replicated SDL profiles,
and larger openings.
Narrow Line Tier IV – All-Aluminum XL
Developed as an all-aluminum Narrow Line system with replication
capability and increased scale.
Alternative metal cladding options allow material selection to respond to architectural intent while maintaining consistent manufacturing standards. Available options include bronze, copper, stainless steel, and other specialty metals. These options are most relevant to the wood-interior Narrow Line tiers where exterior cladding is being selected to support the architectural language of the project.
- Available in bronze, copper, stainless steel, and other specialty metals.
- Welded sash and frame assemblies manufactured consistently across metal options.
- Uniform detailing and corner execution.
- Useful for luxury residential, institutional, heritage, and architecturally driven work.
Technical Summary
Narrow Line Window Family
Welded aluminum frame and sash assemblies
2 3/8-inch from edge of frame to daylight opening
Casement and awning
Available in Tier II – XL, Tier III – Heritage XL, and Tier IV – All-Aluminum XL
Wood interior with aluminum or specialty metal exterior cladding; all-aluminum option in Tier IV
Dual-insulated glazing across all tiers; triple-insulated glazing and laminated glass in Tiers II, III, and IV
Custom and replication SDL layouts in Tier III and Tier IV
Custom residential, luxury residential, heritage, institutional, adaptive reuse, and contemporary all-metal projects
The Narrow Line family can be configured to suit different project requirements, from compact wood-aluminum applications to heritage replication and all-aluminum construction. Contact Synergy Group to review the right tier, glazing package, material direction, and detailing approach for your project.