BUILDING ENVELOPE · TECHNICAL GUIDE
“Thermally broken” describes the frame—not the whole window.
A thermal break reduces direct heat flow through an aluminum frame by separating interior and exterior metal with a lower-conductivity material. Whole-system performance still depends on the frame, glazing, spacer, opening type, size, seals and installation.
What affects the complete assembly.
Frame
Profile depth, thermal-break geometry, corner construction and seals affect the frame contribution.
Glazing
Glass make-up, coatings, gas fill, safety requirements and pane size materially affect thermal and solar performance.
Spacer
The perimeter spacer between glass panes influences edge-of-glass heat transfer and condensation behaviour.
Opening type
Fixed, casement, tilt-turn, sliding, folding and entrance systems use different seals and hardware and do not perform identically.
Drainage
Exterior windows and doors need a coordinated path for water that reaches the frame or sill system.
Installation
Perimeter gaps, membranes, flashing, shims, anchors and interior/exterior seals connect the product to the wall assembly.
Thermal performance is one design variable.
A narrow sightline, very large glass panel, operable configuration and aggressive thermal target can pull a project in different directions. Define priorities early so profile selection, glazing and opening type can be evaluated together.
Common questions.
Does a thermal break eliminate condensation?
No. It reduces conductive heat transfer through the frame, but condensation risk also depends on exterior temperature, interior temperature and humidity, glazing and edge conditions, frame performance and local surface temperatures.
Are all thermally broken aluminum systems equivalent?
No. Systems differ in profile geometry, glazing options, seals, hardware, tested configurations and installation details. Compare the complete specified configuration rather than the label alone.
Why coordinate the sill before installation?
Sill height, drainage, waterproofing, finished floor levels and exterior cladding all meet at the base of the opening. Late changes can compromise both appearance and water management.