Knowledge
Thermal insulation in aluminium systems
Modern aluminium systems offer varying levels of thermal insulation — the key element that determines this is the thermal break.
How does a thermal break work?
Aluminium has high thermal conductivity — without additional measures, a profile would act as a “bridge” carrying heat outward. A thermal break, usually made of glass-fibre-reinforced polyamide, separates the outer and inner profile, forming a low-conductivity barrier. Additional chamber fillers (including foams and aerogel) can further improve insulation.
Glass and profiles — together they determine a window’s performance
The glass surface in a window is usually larger than the profile surface, but that doesn’t mean the profile is secondary. A construction’s high insulation is the result of properly combining all its elements — not just the type of glazing, but also the thermal break, the seals and how the profile itself is made.
Insulation levels in aluminium systems
- System without a thermal break — no break, low insulation. Interior constructions, shop fronts, partitions. Limited scope for energy-efficient glazing.
- System with a thermal break — with a break, enhanced insulation. Exterior windows and doors for residential and commercial buildings. Energy-efficient glazing possible.
- System with high thermal performance — break depends on the system, high insulation. Energy-efficient and passive-house construction. Also supports high-performance glazing packages (e.g. triple-glazed).
For the full range of variants, with a comparison table, see the window systems page.
Note: a construction’s actual thermal parameters depend on the specific system, its configuration, the construction’s dimensions, the type of glazing, the seals used and the quality of installation.
Frequently asked questions
Can any aluminium system have a thermal break?
Yes — thermal insulation isn’t a separate “system”, it’s a configuration variant available within PROMOST’s window, door and façade systems. The same profile system can therefore come without a thermal break (for interior applications) and with a full thermal break (for energy-efficient construction).
What exactly does a thermal break do?
It separates the outer and inner profile with a low-conductivity barrier (usually glass-fibre-reinforced polyamide), interrupting the “bridge” through which aluminium — an excellent heat conductor — would otherwise carry heat outward.
Is thicker glass alone enough for a highly insulating window?
No — the whole window’s performance is determined by the combination of glazing, profile, thermal break and seals. Even energy-efficient glass can’t fully compensate for a profile without the right insulation, which is why high thermal-performance systems are selected as a complete package.
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