Aluminium is the dominant framing material for architectural glazing
in the UAE. It is strong, lightweight, corrosion-resistant, and can be
extruded into complex profile shapes. But it has one significant
disadvantage: it conducts heat approximately 1,500 times more
efficiently than PVC and around 1,000 times more than timber.
In a climate where cooling loads dominate energy consumption and
building energy codes are tightening year on year, this thermal
conductivity is not an academic concern. It is a specification issue
that directly affects compliance, energy performance, and occupant
comfort.
This is where thermal break technology becomes essential — and where
the difference between specifying it well and specifying it loosely can
determine whether a building passes its energy performance targets.
How Thermal Breaks Work
A thermal break is an insulating barrier inserted into the aluminium
profile to interrupt the conductive heat path between the exterior and
interior faces of the frame. Without it, the aluminium frame acts as a
thermal bridge — conducting heat from the hot exterior directly to the
cooled interior, increasing cooling loads and potentially causing
surface condensation.
The most common thermal break material in modern aluminium systems is
polyamide (PA66), typically reinforced with glass fibre for structural
integrity. The polyamide strip is mechanically crimped into channels in
the aluminium profile, creating a structural connection between the
inner and outer aluminium sections while providing thermal insulation
between them.
The width of the thermal break strip is one of the most important
specification variables. Strips typically range from 14mm on basic
systems up to 45mm or more on high-performance systems. A wider thermal
break provides a longer insulating path and better thermal performance,
but it also affects the structural behaviour of the profile and requires
more sophisticated crimping to maintain integrity.
Why It
Matters More in Dubai Than You Might Think
There is a common misconception that thermal breaks matter less in
hot climates than cold ones. The reasoning goes: if the temperature
difference between inside and outside is smaller in Dubai than in, say,
Stockholm, surely the thermal performance of the frame matters less?
This reasoning is wrong for several reasons.
First, the temperature difference is not smaller. A Dubai exterior
wall surface can reach 70-80°C in direct summer sun. With interior
temperatures maintained at 22-24°C, the delta across the frame can
exceed 50°C — comparable to or greater than many northern European
winter conditions.
Second, cooling is more expensive than heating per unit of energy.
Removing heat from a building through air conditioning is
thermodynamically less efficient than adding heat through a boiler or
heat pump. Every watt of thermal bridging through a non-thermally-broken
frame translates directly to additional cooling load, which translates
to electricity consumption, which translates to operating cost.
Third, the regulatory environment is catching up. Al Sa’fat, Dubai’s
green building rating system, sets maximum U-values for glazing that
cannot be achieved without thermally broken frames. The Building Energy
Code provisions tightened in 2024 further reinforce this. Specifying
non-thermally-broken systems on new buildings is increasingly a
compliance risk, not just a performance choice.
Fourth, condensation. In Dubai’s air-conditioned buildings, the
interior surface of a non-thermally-broken aluminium frame can drop
below the dew point of the indoor air. This creates visible condensation
— water running down frames and pooling on sills. It is one of the most
common snagging items on residential projects and is almost entirely
preventable through proper thermal break specification.
What to Specify: The Key
Variables
When specifying thermally broken aluminium systems, the following
variables determine performance.
Thermal break width. As noted, wider is generally
better for thermal performance. A 24mm polyamide break is considered
standard for most applications. Systems with 34mm or 45mm breaks deliver
measurably better performance and are required for the highest Al Sa’fat
tiers. Specify the minimum break width in your performance
specification, not just the target U-value — this prevents value
engineering that substitutes a narrower break with optimistic
calculation assumptions.
Thermal break material. PA66 reinforced with 25%
glass fibre is the industry standard. Some budget systems use PVC or
unreinforced polyamide, which have lower structural strength and may
degrade faster under UV exposure and thermal cycling. Specify PA66 GF25
as a minimum.
Profile geometry. The overall frame depth, the
number of chambers in the profile, and the position of the thermal break
within the cross-section all affect performance. Deeper profiles with
the thermal break positioned toward the centre of the frame generally
perform better than shallow profiles with the break near the exterior
face.
Crimping quality. The mechanical connection between
the polyamide strip and the aluminium profile sections is created
through a crimping process — the aluminium is deformed (knurled) into
the polyamide strip under high pressure. This is a critical
manufacturing step. Poor crimping results in loose connections that
compromise structural integrity, air tightness, and long-term
durability. Factory crimping under controlled conditions with calibrated
equipment produces consistently better results than site crimping or
manual assembly.
Whole window U-value vs frame U-value. Always
specify and evaluate Uw (whole window U-value) rather than Uf (frame
U-value) alone. The Uw accounts for the combined performance of the
frame, the glass, and the spacer bar interaction. A frame with an
excellent Uf but poor spacer bar detailing can produce a disappointing
Uw. Request calculation sheets that show the Uf, Ug, and linear thermal
transmittance (psi value) separately.
The Crimping Process: Why
It Matters
For architects who have not visited a fabrication facility, it is
worth understanding what thermal break crimping involves because it is
the single manufacturing step most likely to affect the long-term
performance of your specified system.
The process works as follows: two aluminium profile sections (inner
and outer) are extruded with longitudinal channels designed to receive
the polyamide strips. The strips are inserted into these channels. The
assembly then passes through a crimping machine that applies controlled
pressure to deform the aluminium into the polyamide, creating a
mechanical interlock.
The precision of this operation determines the structural shear
strength of the thermal break connection, the air tightness of the
profile, and the consistency of thermal performance across every frame
manufactured.
Production crimping requires purpose-built rolling or pressing
machines calibrated to the specific profile and strip dimensions.
Temperature, speed, and pressure must be controlled. The crimping should
be verified through pull-out testing — sampling a percentage of
production to confirm the shear strength meets the system house
specifications.
Why does this matter to architects? Because not all fabricators have
in-house crimping capability. Some purchase pre-crimped profiles from
the system house, which is reliable but limits flexibility and extends
lead times. Others outsource crimping to third-party operations of
variable quality. And some fabricators in the UAE market still assemble
non-thermally-broken systems for projects where the specification does
not explicitly require thermal breaks.
If your specification requires thermally broken profiles, it is
reasonable to ask the fabricator how and where the crimping is done,
what quality control procedures are in place, and whether pull-out
testing is performed. These questions are not onerous — any reputable
fabricator will have clear answers.
Thermal Breaks and System
Selection
Thermal break technology is not a bolt-on feature. It is integral to
the system design. When evaluating aluminium systems for a project,
consider the thermal break capability as part of the system selection,
not as a separate line item.
Premium European systems from manufacturers like Schüco, Reynaers,
Cortizo, and Technal typically offer thermal break widths from 24mm up
to 45mm across their ranges, with the wider breaks available on their
high-insulation product lines. These systems have been designed, tested,
and certified with specific thermal break configurations.
Regional system houses such as Gulf Extrusions, Alumil, and others
offer thermal break options that are tailored to Middle East
requirements. The break widths and profile geometries may differ from
European equivalents, but the underlying technology is the same — PA66
strips crimped into aluminium channels.
The choice between systems should be driven by the project’s target
Uw values, the Al Sa’fat tier being targeted, and the relative
importance of thermal performance versus other factors like sightlines,
hardware compatibility, and maximum glass sizes.
Looking Ahead
As Dubai’s energy code requirements tighten, thermal break quality
will become an increasingly important differentiator between glazing
suppliers. The direction is clear: minimum performance thresholds are
rising, and the margin between “just compliant” and “robustly compliant”
systems is narrowing.
Architects who specify thermal break performance explicitly — break
width, material, crimping standards, and verified Uw values — protect
their projects against both current compliance requirements and future
tightening. Those who leave thermal break specification vague invite
value engineering that may technically comply today but leaves no margin
for tomorrow.
London Architectural Aluminium fabricates and installs premium
aluminium glazing systems for luxury residential and commercial projects
across the UAE. We operate one of the few in-house thermal break
crimping lines in the region, with rapid turnaround times. For technical
consultations or specification support, contact our team.