Preserving History, Embracing Efficiency: W20 TE in Heritage Restoration

• 27 March 2025
• News

Anyone who has had the good fortune to work on the restoration of a heritage building will know that every step of the process requires a careful balance of historical authenticity and modern performance. If these buildings are early 20^th century, it’s highly likely they feature original steel window frames that have weathered decades of exposure.

While these windows undoubtedly contribute to the character of heritage or listed buildings, their age means lack the thermal performance expected in contemporary settings. However, for architects and developers, all is not lost: the introduction of Crittall’s Corporate W20 TE® steel window system presents a perfect fit for heritage restoration projects, offering thermal efficiency, durability and the slender sightlines essential for maintaining a building’s architectural integrity.

A new lease of life for heritage properties

Crittall’s W20 TE® system provides a solution that chimes with history while significantly improving energy efficiency. This advanced steel window system boasts impressive UW & UD values of just 1.4 W/m²K, delivering superior insulation without compromising design. Fully compliant with Approved Document L, W20 TE® is a gamechanger for architects and conservation specialists seeking to enhance sustainability in restoration projects.

Slim sightlines, solid reputation

The beauty of steel windows lies in their ability to blend strength with elegance. The W20 TE® retains the exceptionally slim sightlines synonymous with Crittall Windows, ensuring heritage properties retain their distinctive appearance. This slender profile allows for larger glass areas, increasing natural light while providing the strength required for large-scale installations.

With a life expectancy exceeding 60 years, these steel frames offer unmatched durability. Galvanized and powder-coated in any RAL, BS, or bespoke colour, they withstand the elements while complementing traditional aesthetics. From Grade II listed buildings to period homes, W20 TE® ensures a seamless restoration that preserves a structure’s historic charm.

Energy efficiency meets conservation needs

As we’ve mentioned, one of the greatest challenges in heritage restoration is balancing conservation rules with modern energy standards. Traditional steel windows often fall short in meeting today’s thermal requirements. The W20 TE® system bridges this gap, delivering an energy-efficient solution that meets the highest conservation standards.

Produced using state-of-the-art CNC machinery, these new steel windows achieve a thermal gradient comparable to that of thermally broken steel sections. Additionally, dual weather seals provide enhanced weather performance ensuring properties remain warm in winter and cool in summer. This makes W20 TE® an excellent choice for planners, architects, and conservation officers looking for a modern steel window system that adheres to historic preservation guidelines.

Sustainability and longevity

Sustainability plays a significant role in contemporary construction, and heritage restoration is no exception. As a manufacturer of steel windows, Crittall ensures the W20 TE® system is made from 100% recycled steel, reinforcing the company’s commitment to environmental responsibility.

Additionally, steel’s inherent strength reduces the need for frequent replacements, making it a long-term investment for any restoration project. Crittall’s solid reputation as a leading steel door manufacturer ensures that these new steel windows not only enhance the beauty of historic properties but also contribute to a more sustainable future.

A perfect fit for heritage restoration

Beyond windows, Crittall’s expertise extends to internal doors and complete door systems, ensuring a cohesive approach to heritage restoration. Whether revitalising a historic home or restoring a commercial building with Grade II status, W20 TE® steel windows and doors provide the ultimate combination of heritage aesthetics and cutting-edge performance.

• For more information contact Crittall Windows here, or give us a call on 01376 530 800.