Velux has unveiled a new vacuum insulating glass technology, developed in collaboration with Guardian Glass, at the Dach+Holz. The innovation is designed specifically for roof windows, where higher structural loads and performance demands make advanced glazing solutions essential.

Unlike conventional insulating glass units that rely on argon or krypton gas between panes, this new system uses a vacuum layer to significantly reduce heat transfer. As a result, it delivers insulation performance comparable to triple glazing but within a much thinner and lighter construction. The glass measures just 11.5 mm in thickness, compared to 26.4 mm for standard double glazing and 38 mm for triple glazing with similar performance levels.

Velux will introduce the technology in two variants. The single vacuum glazing option features a slim double-pane design that eliminates the need for a third pane. This reduces weight by approximately 1.5 to 5 kg per window unit, depending on configuration, making installation easier while achieving a Uw value of 1.0 W/(m²K). Additionally, it offers around a 30% lower CO₂ footprint for the insulating glass unit.

The hybrid version combines vacuum glazing with a third pane separated by gas filling. This configuration reaches a Uw value of 0.83 W/(m²K) and delivers sound insulation of 38 dB, while reducing carbon emissions by up to 12% compared to the glass unit alone.

A subtle dotted pattern, created by micro spacers within the vacuum layer, is visible but does not obstruct the view. The technology will debut in 2026 in the UK and Ireland as part of the Velux Heritage range, with further European expansion expected.