Velux Performance Goes Through The Roof

At the Cologne roof & timber expo, Velux unveiled its new vacuum insulating glass technology which is designed to take the energy performance of roof windows…well through the roof.

Velux claims it has redefined energy efficiency and reduced carbon footprint with this development which can achieve the performance associated with triple glazing with just two panes.

Developed in partnership with Guardian Glass, the technology is specifically engineered for roof windows which pose a far more demanding application than façade due to higher loads and structural requirements. It provides high thermal and acoustic insulation with a reduced CO₂ footprint, contributing to more sustainable buildings and improved indoor comfort.

Vacuum fills the gap

This new technology allows Velux to replace the space between glass panes with a vacuum that significantly reduces heat transfer. This enables excellent insulation performance within a much thinner and lighter construction compared to standard triple glazing. Instead of separating panes with argon or krypton gas, this solution uses a vacuum that effectively minimises heat loss.

As a result, the vacuum insulating glass achieves the performance of triple glazing in a slimmer, lighter design. A subtle dotted pattern created by tiny spacers between the panes is characteristic of this technology but does not obstruct the view. Velux will introduce the technology in two variants: a single vacuum glazing solution and a hybrid version. 

Single vacuum glazing

The single vacuum glazing variant is an ultra-thin double-pane design that delivers thermal performance comparable to triple glazing. By eliminating the third pane, this new solution is between 1.5 and 5kg lighter per MK06 unit (depending on the full window construction), making installation easier. 

In addition, it offers approximately 30% lower CO₂ footprint when comparing the insulating glass unit alone. A roof window equipped with this glazing achieves an impressive insulation value of Uw=1.0W/(m²K). The difference becomes clear when comparing thickness as this new glass measures only 11.5mm, versus 26.4mm for standard double glazing and 38mm for standard triple glazing with similar insulation performance. 

It will debut in 2026 in the UK and Ireland within the Velux Heritage range, ensuring architectural authenticity is preserved while delivering superior thermal and acoustic performance for enhanced indoor comfort. 

Vacuum Hybrid Technology

The hybrid version combines the vacuum double glazing with a third pane separated by a gas filling. This construction delivers outstanding thermal insulation and excellent sound reduction while lowering the CO₂ footprint. With a Uw value of 0.83W/(m²K) and a sound insulation rating of 38dB, the hybrid solution offers high energy efficiency and acoustic comfort, comparable with the company’s most efficient glazing, IGU 67, with reduced carbon emissions by 5% compared with a full roof window and by 12% compared with the glass alone. 

A launch date for the German market has not yet been set. Depending on project interest and availability, Velux expects to expand the offering to additional European markets.

Picture: Velux is achieving triple-glazed performance with just two panes for its roof windows.

www.velux.co.uk/professionals