W20 TE for Conservation and Modern Renovations

• 16 April 2025
• News

Walk down any UK street, and you’re almost guaranteed to come across a building that has historic interest. And in a country that has no less than 10,000 conservation areas, there’s an equally good chance that you live among – or even in – such buildings.

Over the years, stringent planning rules have made sure that our unique architectural heritage is preserved. However, older buildings are subject to the ravages of time and need regular maintenance, repair or even renovation to keep up standards.

Windows can be a particular area of concern. Old single-glazed windows look great until winter sets in, then they’re about as thermally useful as a sheet of polythene. The challenge for homeowners, architects and planning officers is in maintaining a building’s historic integrity while ensuring it meets modern energy efficiency and performance standards.

Crittall’s heritage dates back to 1849 when Francis Berrington Crittall began manufacturing metal-framed windows in Essex. By the early 20th century, Crittall had become a defining feature of Modernist architecture, supplying steel windows for many iconic projects. With such a rich legacy in both domestic and industrial buildings, Crittall has long been synonymous with quality craftsmanship and innovation in steel fenestration. This enduring legacy is what makes the W20 TE system such a trusted choice for today’s conservation and renovation projects.

Crittall’s W20 TE conservation windows are designed to fulfil these exacting requirements, offering the classic appearance of traditional steel fenestration with cutting-edge thermal enhancements. Whether restoring a listed home or repurposing a historic industrial site, W20 TE provides heritage authenticity and contemporary comfort.

Meeting conservation standards with W20 TE

Conservation rules demand the retention of a building’s character, often requiring window replacements to match original profiles and sightlines. The W20 TE system builds upon Crittall’s heritage in steel windows, maintaining the elegance of traditional steel profiles while incorporating advanced thermal performance.

By adapting the iconic W20 section using precision CNC technology, the W20 TE achieves a U-value of just 1.4 W/m²K. This significant improvement meets modern energy efficiency standards without altering the distinctive slim sightlines that define period properties. Moreover, the system’s co-extruded dual weather seals and durable polyester powder coating provide additional protection against the elements, ensuring long-term performance in conservation settings.

Why W20 TE is the ideal choice for conservation and renovation

• Heritage compatibility – Matches original steel window designs, ensuring conservation approval.
• Energy efficiency – Advanced thermal enhancement, meeting Approved Document L requirements.
• Unrivalled durability – Galvanised steel construction with a life expectancy exceeding 60 years.
• Customisation – Available in a wide range of colours with bespoke options to suit individual projects.
• Weather performance – Innovative seals prevent draughts and enhance comfort.

For those seeking a conservation-compliant window replacement that respects the past while embracing the future, the W20 TE system is the perfect solution. These beautiful steel windows ensure authenticity, durability and performance in one elegant package.

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