What Is Switchable Glass and How Does It Work?

Switchable glass offers privacy at the touch of a button. As open plan spaces surge in popularity, so does the kind of upscale contemporary design that requires switchable glass. It’s low maintenance, which saves you time and money in a range of niche applications.  

So what is switchable glass and how does it work? It’s a pane of glass that can toggle between transparent and opaque. Applying a low voltage shifts lithium ions between its layers to interrupt the flow of light. Many systems even allow control through your phone. 

Electrochromic glass is the most widely used type in architectural applications, but there’s others worth familiarising yourself with. Generally, switchable glass operates based on three primary mechanisms: electric current, heat exposure and light exposure. To make things easier, this article generally refers to electrochromic glass as switchable glass. 

Switchable glass is a high-end glazing innovation serving the growing demand for flexible spaces that can adapt to different activities and preferences, without the need for physical alterations or additional fixtures. 

  

Electrochromic Glass 

This allows you to change opacity of glass the touch of a button. Inside, there are layers embedded with lithium ions. When you turn on the electricity, these ions move and darken the glass. 

On a more technical level, the process relies on the movement of both lithium ions and electrons within the glass layers. The glass is made up of several thin coatings, including an electrochromic layer and an ion storage layer, separated by an electrolyte. Applying a low voltage causes the ions to shift, darkening the glass, while reversing the voltage sends them back to their original layer, restoring transparency. 

The purpose of electrochromic glass is to give users the luxury of being able to quickly segment areas, usually of a workspace. Since it does not rely on environmental triggers like light or heat, it provides consistent performance regardless of external conditions. 

  

Thermochromic Glass 

Thermochromic glass is more about temperature and energy efficiency; it allows your building to regulate indoor temperatures passively. When it’s hot outside, the glass darkens to prevent excess heat from entering, reducing the need for air conditioning. When it cools, it remains clear to maximise solar heat gain and warm the building. 

In architecture, it’s used for climate control in glass box extensions, conservatories or any space with large glass surfaces that can lead to significant temperature fluctuations. By integrating thermochromic glass, architects can mitigate these issues without relying on mechanical shading devices or active cooling systems. 

This glass incorporates materials like vanadium dioxide, which is transparent at lower temperatures but undergoes a reversible transformation when heated. As the temperature rises, particularly under direct sunlight, the material transitions to a reflective, metallic state. Less infrared radiation enters the space, reducing heat gain. In colder conditions, thermochromic glass can remain clear to allow maximum sunlight and warmth, reducing the need for heating. 

Dynamic modulation of light and heat not only keeps occupants comfortable, but also leads to substantial energy savings. While some blinds and curtains can provide a degree of insulation, they are generally less effective at regulating heat transfer compared to thermochromic glass. They do not prevent solar heat gain effectively during hot weather or retain heat efficiently during colder periods. Increasing your reliance on heating and cooling systems is inefficient by comparison, and contributes to higher energy consumption and costs. 

Over time, the reduced energy consumption offsets the initial investment, making it viable for sustainable building design. Environmental concerns and regulatory pressures are accelerating the adoption of energy-efficient technologies like this kind of switchable glass. Certifications such as LEED (Leadership in Energy and Environmental Design) recognise and reward the use of these kinds of sustainable material technology.  

Thermochromic glass still has its limitations. Like photochromic glass, it lacks manual control. Occupants cannot adjust the transparency according to their preferences, and the aesthetic changes made by the tinting effect may not align with certain design visions. Its reaction time also depends on the weather, rather than immediate needs. 

  

Photochromic Glass 

Photochromic glass contains microcrystalline molecules. UV rays cause electrons in the glass to interact with the silver halide molecules, creating opaque silver particles that darken the glass. This process usually takes around 30 seconds to reach maximum tinting, and reverses over a period of two to five minutes once the UV exposure decreases. This type of glass is widely used for transition lenses in glasses. 

  

Applications 

If you need a privacy upgrade, switchable glass is superior to ‘one way’ mirror glass because it lets in sunlight. Natural light is important for our body clock, and more control you have over your environment, the more relaxed you feel. Electrochromic switchable glass provides instant privacy without the need for physical barriers or additional window treatments like blinds and curtains. This feature is particularly beneficial in settings where transparency is desirable most of the time, and privacy is only occasionally necessary. Reducing distractions through the control of glare and noise further contributes to a conducive work environment.  

The options for customising blinds and curtains to match specific interior design schemes may be limited, and they can quickly become outdated as trends evolve. By eliminating the need for curtains or blinds, switchable glass also looks more streamlined. It aligns with minimalist design principles by reducing visual clutter. 

Blinds and curtains can also require inconvenient manual operation, especially with large windows or hard-to-reach areas. Motorised options are available but add complexity and cost. Traditional solutions cannot modulate light and privacy with the same precision as switchable glass. Physical blinds are either open or closed, offering limited flexibility in controlling the amount of light entering a space or the degree of privacy. 

Worse still, blinds and curtains can suffer from wear and tear due to constant use and exposure to sunlight. Fabrics may fade, become discoloured or weaken, leading to tears and fraying. Mechanical components in blinds, such as cords, pulleys and slats, can malfunction or break, necessitating repairs or replacements. This ongoing maintenance not only incurs additional costs but can also cause inconvenience due to repair downtime and disruption. 

By comparison, switchable glass is more durable, designed to withstand regular use and exposure to environmental conditions without significant degradation. Additionally, the technology can be integrated seamlessly into building automation systems, allowing for effortless control through switches, remote devices, or even voice commands. 

Its applications are diverse, ranging from commercial offices to residential homes. For instance, a glass-walled meeting room can remain transparent during regular operations. When confidentiality is required, the glass can be switched to opaque, ensuring privacy without interrupting the visual continuity of the office layout. It supports the trend towards agile working environments, where spaces need to accommodate a variety of tasks and interactions. 

In retail and hospitality, switchable glass is being utilised to create dynamic displays and adaptable spaces that wow customers. It’s even used in trains to save residents in adjacent buildings from awkward moments, automatically frosting the carriage window while passing by. 

Switchable glass plays a crucial role in healthcare facilities, where hygiene and patient comfort are prioritised. Traditional window coverings like curtains and blinds can harbour dust, allergens and pathogens, posing a risk to sterile environments. By replacing these with switchable glass, hospitals can maintain high hygiene standards while providing patients with control over their privacy. 

The ability to adjust transparency without physical contact is significant in reducing the spread of germs. Switchable glass can be integrated with automated systems, allowing for hands-free operation through sensors or voice commands. This feature enhances both safety and convenience for patients and staff alike. 

In residential settings, privacy is a fundamental concern, especially in bathrooms and bedrooms. Switchable glass offers an elegant solution by allowing homeowners to switch between transparency and opacity instantly. This capability eliminates the need for blinds or frosted glass, which can obstruct natural light or detract from the design. Switchable glass can be used to create dynamic façades, interactive displays, or artistic installations that engage occupants and passersby. 

  

Advanced Types of Switchable Glass 

Beyond the traditional photochromic, thermochromic, and electrochromic glasses, new technologies have emerged that offer enhanced performance and expanded capabilities. Two notable advancements are Suspended Particle Devices (SPD) and Polymer Dispersed Liquid Crystal (PDLC) technology.  

Polymer Dispersed Liquid Crystal technology, on the other hand, incorporates liquid crystal droplets dispersed within a polymer matrix sandwiched between two conductive layers. In the absence of an electric field, the liquid crystals are randomly oriented, causing the glass to appear opaque as light is scattered. When voltage is applied, the crystals align, permitting light to pass through and rendering the glass transparent. PDLC glass offers instant switching and customizable levels of opacity, making it particularly useful for privacy glass in offices, conference rooms and residential spaces. 

The intersection of switchable glass with the Internet of Things (IoT) and AI is also unlocking new capabilities. Smart home compatibility enables switchable glass to interact with voice assistants like Siri. Users can control transparency settings through voice commands or smartphone apps, enhancing convenience and accessibility. 

AI systems are being developed to learn user preferences and optimise comfort and efficiency automatically. Predictive adjustments can be made based on factors such as time of day, occupancy patterns and weather conditions. For example, AI algorithms can anticipate the need to reduce glare in the afternoon or increase privacy during meetings, adjusting the glass settings without manual input. 

Switchable glass can also be used to create dynamic façades, interactive displays or artistic installations that engage occupants and passersby. Dynamic urban landscapes could emerge as buildings with switchable façades change appearances in response to environmental conditions, cultural events or artistic expressions. This adaptability could transform cityscapes into ever-evolving canvases that reflect the vibrancy of urban life. 

  

Case Studies  

Real-world applications of advanced switchable glass technologies illustrate their transformative impact on architecture and user experience. In commercial buildings, iconic structures like the Seattle Tower have integrated electrochromic glass throughout their façades. This implementation allows the building to automatically adjust its transparency based on external light conditions, optimising energy use. Occupants benefit from increased comfort, reduced glare and enhanced views.  

Residential projects have also embraced switchable glass to create modern, energy-efficient homes. For instance, the Smart Home project in Copenhagen incorporates PDLC glass in interior partitions and exterior windows, so their residents can adjust the transparency of walls to reconfigure spaces dynamically. It’s privacy without sacrificing natural light, keeping everyone connected to nature. 

From its early development to the advanced systems available today, switchable glass has continually expanded the possibilities for how we shape and interact with our environments. Its ability to enhance energy efficiency and provide flexibility positions it as a pivotal element in the future of architecture and urban development. 

Integrating switchable glass into new constructions allows for seamless incorporation into the building’s design and systems. Attention to detail during the planning phase can optimise the placement of switchable glass elements, maximising their functional and aesthetic benefits. Be sure to collaborate early with experts like IQ Projects to ensure that your electrical and control requirements are met.  

Whether you’re an architect designing the next landmark building, or someone from another industry intrigued by the possibilities of switchable glass, it’s an exciting product. By exploring its applications and staying informed about developments, you can contribute to a future where our spaces are more adaptable, efficient and harmonious with our well-being. 

Get in touch with us today!