January 18, 2023

Vacuum Glass: Is it the future?

Written by Michelle Martin

Using vacuums in glass units to create an insulated glass panel  

Advances in glass technology have enabled building designers to fulfill the age-old issue of light ingress into dwellings whilst maximising insulation. Today, architects have a plethora of high performance glazing solutions to choose from.

In addition to triple glazing, the latest Vacuum Glazing technology outperforms other glazing with its unequivocal quality of thermal performance.

Vacuum glass showcases one of the latest advances in insulated glass design. In traditional insulated glass panels, two panes of glass are separated via a gas cavity. For modern architectural glazing, this gas cavity is most often Argon which is a heavier gas than air. The heavier gas molecules move more slowly than air, and transfer heat energy to the external face of glass at a slower rate, therefore improving the insulation of the glass.

Vacuum glass replaces this traditional gas filling with a vacuum. Two panes of glass are separated by a vacuum gap which acts as the thermal break. With no particles in the cavity to transfer heat, the insulation levels possible from vacuum glass vastly outperform what can be achieved from a typical argon or krypton filled IGU.

Vacuum glazing can achieve Ug values of 0.4 W/m2K which is currently only possible using quadruple glazing with three gas cavities. However, as the space between the glass units for the vacuum is much thinner than the depth of the gas cavity needed for an IGU (a 0.3mm vacuum cavity vs 12-18mm for gas) the resulting insulated glass pane is 10 times thinner than quadruple glazing.

This offers the construction market an alternative high performance glass option for restoration projects or replacement glazing requirements with high thermal insulation.

Pilkington Spacia™ Vacuum Glazing installed at Old Fellows Lodge in Edinburgh
Image © Pilkington Spacia™

 

Advantages of Vacuum Glass

• Vacuum Glazing is an effective solution for replacing glazing in heritage buildings where the depth of a glass unit is restricted.

 

• Vacuum Glazing can achieve Ug values of 0.4 W/m2K

 

• With less glass, a Vacuum Glazing provides 15% greater light transmission than triple glazing

 

• Vacuum Glazing units are 10 times thinner than a quadruple glazed alternative

 

• The thermal performance of the Vacuum glass does not change when installed at an angle

 

Vacuum Glass vs Triple Glazing

With Ug values of 0.4 W/m2K, Vacuum glazing is often compared to triple glazing for its performance. With enhanced levels of insulation to rival triple glazing, Vacuum glass offers a much slimmer glass unit.

Pilkington's Spacia™ is an example of a Vacuum Glazing product that includes a black 12mm ‘plug’ on the face where the vacuum cavity is created.

 

 

Can I use Vacuum Glazing on My Project?  

Vacuum glazing is a high-performance glazing system that offers a high level of thermal insulation and sound insulation properties, however, it is a new technology and there are some restrictions on size and scale of glazing orders that need to be considered when using this technology. Currently, the maximum sizes per pane of vacuum glazing are 2.4m by 1.45m, which is smaller than the typical size of glass used on a modern architectural glazing project today.

Furthermore, every order of vacuum glass is currently manufactured directly for its purpose, and there is not a stock of the product with glass suppliers. This means that small orders of vacuum glazing may be cost prohibitive for some projects. At present, vacuum glazing is more suited to larger glass orders until it becomes a more well-known and well-used option for glazing projects.

As demand for larger vacuum glass panes increases, and with continued research into strengthening vacuum insulated glass on a bigger scale, we can expect to see further advances in the not-so-distant future. It is important to consult with a professional glazing company or a qualified engineer to determine whether vacuum glazing is a suitable option for your glazing project and to understand the limitations of this system.

 

For more technical details, talk to an expert today! 

 

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