What Is Thermally Broken Aluminium?

If you’re researching aluminium windows or doors, you’ll almost certainly come across the term “thermally broken aluminium.”

But what does it actually mean — and why is it so important?

In short, thermal breaks are what make modern aluminium systems warm, efficient, and suitable for UK homes.

What does “thermally broken” mean?

Aluminium is naturally a conductor of heat.
On its own, it would allow warmth to pass straight through from inside to outside.

A thermal break solves this problem.

Thermally broken aluminium frames contain a non-conductive barrier (usually a high-strength polyamide strip) that separates:

• The internal aluminium profile

• The external aluminium profile

This barrier breaks the path of heat transfer, dramatically improving thermal performance.

Why thermal breaks matter

Without a thermal break, aluminium frames would:

• Lose heat quickly

• Feel cold to the touch

• Create condensation issues

• Fail modern building regulations

Thermal breaks are what allow aluminium doors and windows to be:

• Energy efficient

• Comfortable year-round

• Fully compliant with UK standards

How thermal breaks improve energy efficiency

Thermally broken aluminium frames help to:

• Reduce heat loss

• Maintain internal temperatures

• Lower heating demand

• Improve overall U-values

When combined with modern double or triple glazing, they deliver excellent real-world performance, even in large glazed openings.

Do all aluminium systems have thermal breaks?

All modern, high-quality aluminium doors and windows should be thermally broken — but not all systems are equal.

The effectiveness depends on:

• The depth of the thermal break

• The quality of the insulating material

• Overall frame design and engineering

Cheaper systems may use:

• Narrow or poorly designed breaks

• Less efficient insulation

• Outdated profile designs

This is why system choice matters.

Thermally broken aluminium vs uPVC

uPVC is naturally insulating, while aluminium relies on engineering to achieve performance.

With a proper thermal break:

• Aluminium can match or closely approach uPVC thermal performance

• Aluminium offers slimmer profiles and greater strength

• Aluminium allows larger glass panels and modern designs

This makes thermally broken aluminium ideal for:

• Bifold doors

• Sliding doors

• Large windows

• Contemporary homes

Does thermal break affect condensation?

Yes — in a good way.

By reducing temperature transfer:

• Internal frame surfaces stay warmer

• Condensation risk is significantly reduced

• Comfort levels improve near large glazed areas

Good ventilation is still important, but thermal breaks play a major role.

Are thermally broken aluminium doors and windows secure?

Yes.

Thermal breaks do not weaken the frame.
They are engineered into the profile while maintaining:

• Structural strength

• Rigidity

• Security performance

High-quality thermally broken systems can still achieve:

• PAS 24 security testing

• Multi-point locking

• Support for laminated glazing

Final verdict: what is thermally broken aluminium?

Thermally broken aluminium is what makes modern aluminium doors and windows:

• Warm

• Energy efficient

• Comfortable

• Fully suitable for UK homes

Without a thermal break, aluminium simply wouldn’t perform to today’s standards.

Choosing the right aluminium system

At Home Build Doors, we only supply thermally broken aluminium systems, ensuring excellent thermal performance, slim sightlines, and long-term durability across bifolds, sliding doors, windows, and entrance doors.