Warm Core aluminium windows, bi-folds and doors: a warmer aluminium solution

Aluminium has long been prized for its strength, slim sightlines and premium finish, but its thermal performance has lagged behind other materials. Warm Core aluminium windows, bi-folds and doors change that balance, delivering the architectural look of aluminium with far better insulation. If you want high-end aluminium aesthetics without the heat loss, Warm Core deserves close attention.

What is the Warm Core system?

Warm Core is a purpose-designed dual-core aluminium system built from the outset to reduce thermal bridging and improve overall energy efficiency. Instead of relying solely on a narrow polyamide thermal break, Warm Core uses a full-width, multi-chambered insulating core combined with high-grade aluminium outer faces. The result is a composite frame that looks and performs like aluminium while retaining significantly improved thermal properties.

Key technical features

• Multi-chambered insulating core that replaces conventional small thermal breaks.
• Optimised 70mm front-to-back sash frame depth for balanced proportions and performance.
• High-grade aluminium outer faces that provide structural rigidity and slim sightlines.
• Robust surface finish with powder coating thicknesses of 60–80 microns, exceeding typical marine-grade standards.
• Corrosion-resistant fixings, precision-engineered multi-point locks and purpose-designed hinges for long-term reliability.

Thermal performance and compliance

Warm Core’s full-width insulating core is the reason it outperforms traditional aluminium frames. Independent data shows Warm Core products can be approximately 25% more thermally efficient than many conventional aluminium systems. That improvement helps retain heat inside the home, reduces cold spots and supports compliance with Building Regulations across the UK. For homeowners this can mean lower heating demand and a more comfortable internal environment.

Strength, durability and guarantee

Strength has not been sacrificed in the pursuit of thermal efficiency. The Warm Core design places aluminium where it contributes most to structural rigidity while the insulating core takes on the thermal role. Fixings and moving parts have been selected to resist corrosion and wear, and the powder-coated finish is engineered to stand up to the elements.

Warm Core products are supplied with a 10 Year Guarantee covering materials and surface finish, offering peace of mind that the frames are designed to last.

Hi‑tech elegance: aesthetics and practical design

One of the strongest selling points of aluminium is its refined, architectural look — slim profiles, crisp lines and wide expanses of glazing. Warm Core preserves those aesthetic advantages while addressing energy performance. Typical applications include large fixed picture windows, sash-style openings with multiple openers, and premium folding sliding doors where slim sightlines are essential.

Thoughtful door engineering

Warm Core bi-folds and sliding doors have been designed with practical use in mind. When doors are stacked open, the sashes align neatly and are held parallel using discreet magnets so they look tidy and operate smoothly. Open ends of door sashes, which are hidden when the door is closed, are finished in uniform black for a considered, uncluttered appearance.

Where Warm Core works best

Warm Core is well suited to both contemporary new-build projects and replacement schemes where the client wants the aluminium aesthetic without compromise on insulation. It is appropriate for residential extensions and conservatories as well as commercial glazing projects that demand slim frames and strong structural performance.

Benefits at a glance

• Aluminium appearance with improved thermal insulation.
• Slim sightlines and architectural styling for modern schemes.
• Robust construction and corrosion-resistant components.
• Suitable for bi-folds, sliding doors and a wide range of window types.
• Backed by a 10 Year Guarantee on materials and finish.

Next steps: specification and installation

If you’re considering Warm Core aluminium windows, bi-folds or doors for your property, a site survey and detailed quote will establish the right specification for thermal performance, sightlines and hardware. We can advise on glazing options, colour finishes and threshold solutions to suit both domestic and commercial projects.

To discuss your project or to arrange a survey, please contact us. For further information about our aluminium range and installation services see our Aluminium windows and doors page.

Discover the difference

Warm Core brings together the best of both worlds: the premium finish and structural strength of aluminium with an innovative insulating core that significantly improves thermal performance. For homeowners and specifiers seeking elegant, durable glazing without the thermal compromise, Warm Core aluminium windows, bi-folds and doors are a compelling choice.