The window and door industry and related fields have considered the concept of vacuum insulating glass (VIG) for decades. Despite prospects of extraordinary energy efficiency and surprisingly adaptable construction, the elusive technology has never quite taken hold in the broader public consciousness--until now.
So, what does VIG look like today? How does it work? What does it offer to a window or door design?
Below are answers to these and other frequently asked questions about vacuum insulating glass.
How does vacuum insulating glass work?
The most familiar item in your home or office that would compare to vacuum insulating glass is an insulated coffee mug. In VIG, a small, airless space is created between two panes of glass. This is called a vacuum. The vacuum dramatically limits the amount of thermal energy that can pass through the glass.
Vacuum insulating glass is often used in conjunction with a low-emissivity (low-E) coating that reflects heat from solar radiation. Compared to traditional insulating glass (IG), VIG also keeps the center of glass (COG) temperature warmer, limiting thermal energy loss from convection. The vacuum space itself is the most novel feature, removing all substances--including air--from between the glass, limiting thermal energy loss from conduction.
So, just as an insulated coffee mug keeps hot beverages warm, when an interior space is heated, less warmth will be lost through vacuum insulating glass. And just as an insulated coffee mug keeps chilled beverages cool, when the sun beats down on VIG from the exterior, the air-conditioned interior will remain cooler longer. VIG helps maintain both types of climate-controlled spaces!
How does vacuum insulating glass compare to other types of insulated glass?
Vacuum insulating glass products represent another path for windows and doors to meet heightened energy requirements and create truly comfortable environments. When incorporated into windows and doors, VIG helps a variety of built environments use their energy efficiently, improve occupant experiences, and more.
Simulations of vacuum insulating glass in window and door systems confirm significantly better performance than the best dual-pane argon-filled IG units. When considering the total U-value--which helps identify how well a building material insulates--VIG can provide an improvement greater than 0.06. This makes it a suitable alternative to triple pane IG.
Why was vacuum insulating glass developed?
Vacuum insulating glass directly addresses the energy use--and waste--of buildings. According to the International Energy Agency, buildings are responsible for consuming about 30 percent of the world’s energy. In turn, 39 percent of global carbon dioxide greenhouse gas emissions can be attributed to the materials, construction, and operations of buildings according to a report from the World Green Building Council.
When analyzing where buildings experience energy loss, windows are one of the primary elements to consider. Windows often allow too much thermal energy to escape or enter a building, reducing the efficacy of climate controls. Addressing this disadvantage through innovation is critical.
Do designers use triple pane instead of vacuum insulating glass as a high-performance glass option?
While vacuum insulating glass compares to triple pane glass in some ways, many VIG options also offer design and customization options that triple pane does not. Because VIG only requires two panes with a small gap, it could fit into standard sashes or historical single pane frames. The fewer materials required in its manufacturing also represent lower embodied carbon.
Is vacuum insulating glass durable?
Yes--manufacturers of vacuum insulating technologies have explored different glass treatments to ensure VIG compares to traditional IG in terms of strength and longevity. Relatedly, some VIG technologies can be implemented into window and door products using standardized and time-tested glazing techniques.
Are there any limitations to vacuum insulating glass?
Like some other specialty glass options, current vacuum insulating glass technologies often have restrictions on size and shape. Other custom options such as divided lite patterns might also be limited.
What is noticeably different about VIG versus traditional glass?
Different manufacturers will vary their approach to vacuum insulating glass, but there are a few unique elements that you may want to keep an eye out for when considering your options.
Creating a vacuum between two panes of glass does require some specialized modifications. There may be a small, covered hole--often called a “port”--on the surface of the glass through which the cavity was evacuated. There are likely some visible structures within the glass that hold the panes apart. Lastly, there is likely a desiccant of some sort to absorb any substances that may remain between the glass as the vacuum is created.
Manufacturers work to minimize the visual and structural intrusion of these elements, allowing the vacuum insulating glass to appear as similar as possible to standard, familiar glass options.
What is the future of this technology and related variations at Kolbe?
Kolbe is constantly exploring new ways to offer high-performance options across our product lines. Connect with your local Kolbe dealer to learn more about the latest innovations available for your next project.
