Preserving historic aesthetics. Improving thermal performance.

Historic windows are an important part of a building’s architectural character. Replacing single glazing with modern insulating glass units presents a particular challenge: improving thermal efficiency while preserving the original appearance and proportions of the window. 

The challenge

Heritage glazing often requires narrow cavity insulating glass units (IGUs) with reduced sightlines. The available space within the existing window construction can be very limited, while the proportions and visual character of the original window need to be retained.

For insulating glass manufacturers, this creates a demanding combination of requirements: reduced spacer bar dimensions, reliable processing, and durable edge seal performance within a carefully defined IGU construction. 

The solution

SP34 is a rigid warm edge spacer specifically developed for narrow cavity insulating glass units used in heritage applications. Available in 4 mm, 6mm and 8mm. With a spacer bar height of just 3 mm, SP34 has been specifically engineered to support reduced sightline insulating glass constructions, helping manufacturers meet the dimensional and aesthetic requirements of heritage glazing.

The result is a solution that brings warm edge technology into applications where aesthetics, restricted installation space and modern performance requirements all need to work together.

Developed for heritage insulating glass

SP34 has been developed for use in defined narrow cavity IGU systems where spacer bar dimensions, edge seal design, and long-term durable performance are important. The  SP34 system has been tested for the relevant requirements of EN 1279 parts 2,3 & 6

This makes SP34 particularly relevant for historic buildings, conservation areas and restoration projects where improving the glazing should not come at the expense of the original appearance but a fully certified unit is required

Warm edge technology for heritage glazing

Replacing single glazing with appropriately designed narrow cavity insulating glass units can help improve the thermal performance, reduce heat loss, reduce condensation, and improve indoor comfort while preserving the character of historic windows. For window and insulating glass manufacturers, this creates new possibilities for modernizing historic glazing while respecting its architectural character.

At a glance

• Rigid warm edge spacer designed for heritage glazing
• Available in 4 mm, 6 mm and 8 mm widths
• 3 mm spacer height reduced sightlines
• Supports narrow cavity IGUs with reduced sightlines
• Designed to preserve traditional window aesthetics
• Rigid construction supports efficient manufacturing
• Fully Certified EN1279 part 2,3 & 6
• Modern performance. Historic character.

SP34 brings together the demands of heritage conservation and modern insulating glass technology, helping manufacturers create glazing solutions that respect the past while improving comfort for future generations.