Where Thermal Fits in the JL Range

Essential is JL’s practical standard-aluminium range. Thermal introduces a thermal break through the aluminium frame for stronger thermal separation. Thermal Plus is reserved for higher-specification project requirements where a more advanced frame and glazing package is appropriate.

Compare all three JL window series →

What Is a Thermally Broken Aluminium Frame?

Aluminium is strong, durable and well suited to slim window and door profiles, but it also conducts heat. A thermally broken frame separates the internal and external aluminium sections with a lower-conductivity insulating section. This interrupts the direct aluminium-to-aluminium heat-transfer path through the frame.

Thermal Frame + Glass Work Together

A thermal break improves the frame component, while double glazing and Low-E coatings address the glazed component. The complete result depends on the frame, glass makeup, opening style, size, seals and installation. For this reason, JL separates whole-window U-value and SHGC data from general glass-only claims.

View JL whole-window thermal performance data →

Thermal Window Options

Thermal Door Options

Thermally broken door systems are available for suitable sliding and hinged-door configurations. Larger glazed openings require coordinated consideration of panel size, glass weight, hardware, sill, drainage, structure and installation.

Thermal sliding doors →   |   Compare JL aluminium doors →

Performance & Standards

Thermal performance and structural/weather performance are separate specifications. Selected JL configurations are supported by published whole-window U-value and SHGC data, while selected window and door configurations have AS 2047 performance results covering serviceability, air infiltration, water penetration and ultimate strength.

View AS 2047 performance summary →

When Should You Consider Thermal?

• The project energy report requires stronger whole-window performance.
• Frame heat transfer is an important design consideration.
• Double glazing or Low-E glass is being specified as part of a coordinated performance package.
• The project is comparing standard aluminium with a higher-performance frame system.
• The architectural brief calls for a more performance-focused window and door package.

Do I Need Thermal or Thermal Plus?

Not every project requires the highest specification. The right choice depends on the energy report, opening size, glass, configuration and design brief. Send JL the project information and we can compare the appropriate product family without exposing internal profile codes.