Improving Window Efficiency: Vacuum Insulated Glazing
- alanrchrist
- 4 minutes ago
- 2 min read

ACA is constantly researching innovative approaches to improving the energy efficiency of our projects, and there have been some recent innovations in exterior glazing that have the potential to accelerate the movement towards net zero buildings. Vacuum insulated glazing (VIG) is a type of window glazing that uses a vacuum in a thin space between two panes of glass to achieve high levels of insulation. VIG can greatly improve the R-value relative to existing single or double-pane glazing, while providing an aesthetic appearance which is comparable to single-pane glazing. As an example, Luxwall VIG units can provide an R-18 R-value, and a typical lite is only ¼” thick, which is comparable to single-pane glazing. This is a 5x performance improvement over a typical double-pane IGU and an 18x improvement over single-pane glazing. VIG units typically incorporate a 1 mm air space with microspacers, and a vacuum is created in this space to minimize air transfer. The perimeter seal of the VIG unit typically has a strength of 3,000psi, which is 20x stronger than a typical double or triple-glazed IGU, so it is not prone to deterioration. In addition, VIG units have solar heat gain coefficients and STC ratings which are comparable to much thicker double or triple-pane IGU’s. Finally, VIG units can be used for reglazing, sash replacement, or new construction windows, and their cost is $17-30/SF, which is fairly affordable, given their level of performance.

VIG technology has been available in Europe and Japan for over 20 years, and the product is now being incorporated into windows that are manufactured in the United States. Luxwall Enthermal, Pilkington Spacia, Vitro Vacumax, Guardian Vacuum IG, and Haanglas Basic are commonly available VIG product lines, and the market for their products is quickly expanding in the US. Window companies such as Heirloom, Kolbe, Cascadia, and Velux have recently announced partnerships with VIG manufacturers, and these partnerships with window manufacturers will proliferate as the technology develops. ACA is excited about the potential for this product in both new construction and renovation projects, as it represents a substantial improvement to window efficiency, while making Passive House certification a much more achievable goal for many homeowners.