Steel Windows and Doors: What to Look for in a Premium Product
Premium steel windows and luxury steel doors have become defining features of contemporary and heritage architecture alike. Their appeal is clear: slender sightlines, material integrity and a design aesthetic that works across modern minimalism, classical proportion and industrial character.
But the word premium is often used loosely. True high-end glazing stands apart through engineering quality, long-term performance, and attention to detail at every stage – from the steel itself to the surface treatments that protect it.
Below, we look at the key markers of a genuinely premium steel system, with particular focus on the ultra-luxury finishing processes behind MHB Steel – one of the world’s most advanced steel glazing manufacturers, and Cotswold Windows’ chosen partner.
5 key indicators of a premium steel glazing system
1. The right surface treatment
When specifying steel glazing, durability is paramount. Steel is inherently strong, but without proper preparation and coating, even a beautifully engineered system can succumb to corrosion, especially in Britain’s variable climate.
MHB’s C5 surface treatment: industrial-level protection
One of the clearest markers of a premium product is the surface treatment. MHB applies a Qualisteel C5-rated protective process, the same category used on oil rigs in the North Sea – some of the harshest environments in the world.
A C5 treatment delivers:
- Exceptional corrosion resistance
- Long-term durability even in coastal or exposed environments
- Dramatically extended lifecycle
This level of protection is far beyond typical architectural coatings and ensures that MHB steel windows and doors remain structurally sound and visually flawless for decades.
2. Ultra-premium paint finishes
Where most steel systems rely on standard powder coating, MHB takes an entirely different, hand-crafted approach – one that elevates premium steel windows into a true luxury product.
The Rembrandt coating finish
MHB’s unique Rembrandt coating is an ultra-premium finish, created in-house by MHB and inspired by the Dutch master, made using actual particles of precious metals such as bronze and brass. Through various sanding, polishing, and patina techniques, designers can achieve an almost limitless range of textures, structures, and colour effects.
What makes it extraordinary:
- Each batch is mixed by hand, creating a bespoke blend with a depth and richness that is unique each time
- Applied in multiple layers by hand for tone variation and a soft, luminous sheen
- A genuinely artisanal process – not industrialised, not mass-produced
- Unique to MHB; no other steel system offers a comparable finish
For clients seeking luxury steel doors or a statement glazing installation, the Rembrandt finish delivers an unmistakable premium feel.
Bronze & brass finishes with historical authenticity
Beyond surface aesthetics, some finishes also carry architectural heritage value. MHB’s bronze-toned coatings, enriched with real bronze particles, echo the appearance of traditional metalwork found in heritage properties. This makes them an ideal specification for:
- Listed buildings requiring sympathetic enhancements
- Period homes where authenticity matters
- High-end renovations seeking where a heritage finish is important
Read more about steel’s broad appeal in our blog on Why Steel is back in demand for modern and heritage homes.
3. Engineered for longevity
A key part of choosing high-end glazing is understanding lifecycle value. MHB’s thermally insulated steel profile systems have achieved a 100+ year Service Life Prediction (SLP), independently assessed by ABT under ISO 15686-2.
According to MHB, the SLP certification has been achieved based on the following unique characteristics:
- MHB uses solid steel and solid stainless steel instead of folded thin-walled sheet material.
- As solid steel is used, the surface treatment reaches and protects every inch of the profile system.
- All pre-treatment and surface treatments take place at the same production site; the MHB factory. This also means there is no transport necessary between processing steps, decreasing the risk of contamination.
- Application of a high quality and sustainable top coating (Qualicoat 2).
- MHB applies regular independent quality testing. This ensures the highest quality.
4. Thermal performance and compliance
One of the biggest challenges with steel windows historically has been meeting modern insulation standards. Many traditional systems – including well-known names like Crittall – struggle to meet updated Part L regulations without significant compromises.
MHB systems, however, are engineered for today’s requirements, with a unique patent thermal break system, high-performance glazing options and full Part L compliance across the range.
This makes them suitable for luxury new builds and contemporary extensions as well as heritage properties – see more in our blog Are Heritage Style Steel Windows Compliant with Building Regulations?
5. The value of a specialist installer
A premium product demands a premium installation. The best steel system in the world won’t perform to its potential unless installed by experts with a deep understanding of the material, the engineering, and the finishing process.
As one of only a small number of MHB partners in the UK, Cotswold Windows brings:
- Decades of experience in complex architectural glazing
- Precision installation aligned with MHB’s exacting standards
- Specialist knowledge of large-scale, design-led steel and glass systems
- A consultative approach tailored to architects, designers and homeowners
This level of partnership ensures a seamless journey from specification to installation.
Setting the benchmark for premium steel windows
Premium steel windows and luxury steel doors are defined by more than slender sightlines. True quality lies in the engineering, the corrosion protection, the finishing and the lifecycle performance.
MHB Steel brings these attributes together in a way few systems can match – combining artisanal finishes, rigorous surface treatments and a proven 100+ year life expectancy. Read more about what makes MHB Steel Windows & Doors such a premium product in our recent blog.
Installed by Cotswold Windows, the result is a high-end glazing solution that meets the demands of architects, designers and homeowners who expect enduring performance and exceptional design.
Looking for a premium finish? Contact us about your next project.
