Smart Glass Compared: How It Works, Costs, and Uses

From clear to milky white at the flip of a switch

PDLC stands for polymer-dispersed liquid crystal. A liquid crystal layer sits inside the glazing. Without power, the crystals are randomly oriented and scatter light, making the glass look milky white. When powered, they align, allowing light through and restoring a clear view.

Gauzy PDLC Smart Glass is a representative product. Its specifications and available options are listed below.

Privacy partitions and projection storefronts

PDLC makes it easy to control visibility. An office can stay open and transparent during the day and turn milky white for a meeting. Bathrooms can frost over when occupied, bedroom partitions can provide privacy at night, and hospitals can replace some fabric curtains with switchable glass. The physical boundary stays in place while the sense of openness changes.

In its milky white state, PDLC also diffuses light and can work with a projector. A storefront can display merchandise through clear glass, then become a frosted projection screen for advertising. One pane serves both display and projection purposes.

Apply switchable privacy to the glass already in place

PDLC film uses essentially the same principle as switchable glass, but it is installed differently. The film adheres to existing glass, so adding privacy does not require removing windows, replacing frames, or changing the entire pane. That makes it practical for home and office retrofits.

Film is an accessible way to add clear-to-frosted switching without remodeling. Power, wiring, and edge finishing still need attention. Material test results should not be treated as a direct measure of the installed system’s service life.

Blocking the view does not necessarily block solar heat

Standard PDLC primarily changes how light scatters. The milky appearance obscures the view, but substantial light may still enter the room. Switchable glass should not automatically be treated as high-performance solar-control glazing.

PDLC works well when a bathroom, bedroom, or conference room needs privacy. To make a west-facing room noticeably cooler, compare solar-control PDLC, SPD, electrochromic glass, and Low-E glass combined with switchable technology. Check the solar heat gain performance of the complete glazing assembly.

Staying clear usually requires continuous power

Most conventional PDLC products are milky white when off and clear when on. This provides privacy automatically during a power outage, but keeping the glass clear requires ongoing power.

Power demand is usually modest. At about 3 W/m², a 10 m² glass wall draws roughly 30 W. When designing the controls, factor in how many hours each day the glass should remain clear.

Factory material pricing is only part of the budget

These are mainly factory or business-to-business quotes. They typically exclude shipping to destinations such as Japan, cutting, customization, controllers, transformers, wiring, installation, frames, electrician services, and after-sales support. A material price of around $100–200/m² on Taobao, 1688, or a factory listing is not an installed residential price in Japan.

The same price unit can cover very different work

A Japanese smart film supplier’s July 2026 price guide put the film alone at approximately $764–1,273/m², with installation, electrical work, controllers, travel, and on-site fabrication charged separately.

Other Japanese installers have published market estimates equivalent to $191–509/m². The wide difference reflects product grades, installation scope, and whether controllers are included. A per-square-meter figure alone is not enough to judge value.

Small jobs are not necessarily inexpensive. One or two panes still require a site visit, electrical work, and controls. A full conference-room glass wall can spread those fixed costs over a larger area.

Material grade, installation, and warranty all affect cost

Premium versions often add lower haze, scratch protection, about 99% UV protection, better infrared blocking, engineering support, and longer warranties. Transformers and wiring may cost extra. Prices can differ by a factor of three to five across product grades and project scopes.

Like adjustable sunglasses for a window

SPD stands for suspended particle device. It gradually darkens from a relatively clear state, continuously adjusting the light entering a space. Even when darkened, the glass preserves the outdoor view while reducing intense light and glare.

This suits floor-to-ceiling windows, skylights, panoramic car roofs, aircraft, yachts, and sunrooms. Representative Gauzy SPD specifications follow.

Decide whether you need privacy or less sunlight

PDLC changes from clear to milky white; SPD gradually darkens. Both control light, but a switching demonstration alone does not establish whether they suit the same application.

Usually quoted by project

Industrial SPD products such as Gauzy’s are typically priced per project, with no single public retail rate. Consumer-market pricing information from 2025–2026 translates to roughly $538–1,615/m².

This is only an early budgeting guide. Automotive glazing, curved panels, and large buildings have very different specifications and delivery requirements. Controls and installation also need separate checks. SPD remains a relatively expensive building and remodeling material.

From individual windows to whole-building automation

Electrochromic glass changes its light transmission in response to an electrical signal. Representative products include Saint-Gobain’s SageGlass and View Smart Windows. With a control system, the windows can automatically adjust their tint as conditions change.

The system considers time, sun direction, light levels, cloud cover, building orientation, temperature, and reflected light to determine which panes should darken and by how much. It brings automatic brightness adjustment to a building’s windows.

Darker glass can also reduce incoming solar energy

SageGlass is a representative architectural electrochromic product. In a typical double-glazed configuration, visible light transmission can fall from about 60% in the clear state to about 1% at the darkest setting, while the solar heat gain coefficient (SHGC) falls from about 0.41 to 0.09. The change affects both room brightness and solar heat gain.

One triple-glazed configuration provides the data below, with a maximum size of about 1.83 × 3.0 m.

One pane can have different tint levels from top to bottom

Harmony supports a vertical tint gradient. When afternoon sunlight enters through the top of a window, the upper area can darken, the middle can remain moderately tinted, and the bottom can stay clear so seated occupants keep their view.

Harmony offers 8 tint states and can work with building management systems (BMS), BACnet, rooftop light sensors, and automated control algorithms. Wall controllers and smartphone control are also supported.

A full clear-to-dark transition usually takes minutes

A typical-size SageGlass pane generally needs several minutes to move between its lightest and darkest states. Temperature and pane size also affect speed. The tint deepens gradually, unlike PDLC’s millisecond privacy switching.

Adjusting throughout the day

Exterior windows need to respond to the sun’s position: east-facing glass darkens in the morning, west-facing glass in the afternoon, and higher light transmission returns on cloudy days. A transition lasting several minutes generally fits this gradual pattern of building control.

Electrochromic glass therefore suits skyscrapers, offices, hotels, airports, hospitals, schools, and premium residential curtain walls. Its strengths are managing daylight, solar heat gain, and glare across large glazed areas.

Indoor and outdoor brightness changes the view at night

SageGlass is not fully opaque even at around 1% visible light transmission. It may be difficult to see inside during the day, but at night, with lights on indoors and darkness outside, people may still be able to see in.

Bathrooms, bedrooms, and changing rooms should not be specified using minimum light transmission alone. Spaces that need visual privacy should use products designed for that purpose, such as PDLC, rather than treating dark electrochromic glass as a direct substitute.

Glass, controls, cloud services, sensors, and software working together

View combines switchable glazing with a building-wide control system, allowing each window to be controlled independently. In a typical four-state configuration, visible light transmission is about 52% in Tint 1, 30% in Tint 2, and 6% in Tint 3, with an additional darker Tint 4 state.

The system automatically adjusts the glass using cloud cover, sun position, reflections from nearby buildings, light levels, and how far sunlight penetrates the room, reducing the need for manual adjustments.

• Published figures indicate up to about 99.5% sunlight blocking under high-glare conditions.
• Published solar radiation blocking can exceed 90%.
• Specific building models show annual energy savings of up to about 18%.
• Under specific conditions, peak cooling load reductions reach about 23%.

These are upper-end project or model figures in product literature. Actual results depend on orientation, climate, glazing configuration, and control strategy; they should not be assumed for every building.

Electrochromic glass is already used in major office buildings

NSG Group partnered with View to install View Smart Glass at Tokyo’s Kudan Kaikan Terrace. The project uses four tint states, with visible light transmission as low as approximately 1%, providing a real example of electrochromic glazing in a large Japanese office building.

The glazing specifications and controls determine the budget

SageGlass is generally quoted individually based on area, double- or triple-glazed construction, Low-E options, controls, glass specifications, and building management requirements. There is no single unit price.

These ranges are budgeting references from existing market information. Smart glass also requires allowances for wiring, controls, and installation. Electrochromic glazing mainly targets midrange to premium buildings, so the budget should cover the complete window and control system.

Roughly one-second switching with relatively neutral color

eyrise uses liquid crystal technology associated with Merck. Fast switching is a key feature of its solar-control glazing. A typical configuration can reduce visible light transmission from about 57% when clear to about 2% when dark, in approximately 1 second, while maintaining relatively neutral color through the transition.

Some early electrochromic products took around 15 minutes to switch, while later products often take several minutes. A response measured in seconds better suits spaces that need quick adjustments. Size, temperature, and test conditions still affect actual speed.

Specify solar-control and privacy products separately

Published specifications for some eyrise solar-control products include power consumption of about 1 W/m², maximum glass dimensions of about 1.6 × 3.5 m, and a U-value as low as approximately 0.5 W/(m²·K) in certain configurations, with 48 V DC control, BMS, KNX, and 0–10 V dimming support.

The i350 privacy series has maximum dimensions of about 1508 × 2904 mm, a thickness of about 17 mm, and a clear-to-privacy switching time of approximately 1 second. Its privacy function should be distinguished from the solar-control range; specifications from separate models should not be combined into one product’s capabilities.

eyrise primarily serves premium dynamic glazing projects, with prices typically provided through project quotes.

Integrating a switchable film into automotive glass

AGC Digital Curtain is a representative automotive smart glass product; related products were previously known as WONDERLITE Dx. Two glass layers enclose a special switchable film that quickly changes between clear and shading or frosted states, depending on the vehicle and configuration.

Relevant configurations can block about 99% of UV radiation in either state. The switching function is integrated into the glazing, providing another way to control panoramic roofs and side windows.

From panoramic roofs to roll-down rear windows

The technology has been used in the Toyota Harrier’s panoramic roof and the Toyota Century’s rear door windows. The Century is also an important production application of switchable glazing in roll-down vehicle windows. AGC’s 2026 corporate materials continue to list related products.

• Reduce glare and improve comfort in bright conditions.
• Lower solar heat gain through appropriate glazing configurations.
• Provide additional rear-seat or panoramic-roof privacy on demand.
• Reduce reliance on conventional sunshades.
• Help reduce the vehicle’s air-conditioning load.

These products mainly belong to automakers’ OEM supply chains. Consumers generally obtain the feature through vehicle options, rather than buying a universal smart glass pane to replace a car window themselves.

Separate historical product information from current availability

Searches for Japanese switchable glass still often turn up NSG’s UMU. This was a well-known PDLC product. Earlier specifications listed an opaque-to-clear transition of about 1 millisecond and a clear-to-opaque transition of about 10 milliseconds.

UMU shipments ended in March 2025, bringing roughly 30 years of product history to a close. A page recommending UMU in 2026 may be using old information; a past product description does not establish current availability for a new purchase.

Homes, offices, commercial spaces, and cars

• Home bathrooms: PDLC switches between everyday transparency and frosting during use, reducing the need for blinds or curtains.
• Bedroom and living-room partitions: PDLC lets smaller homes shift between openness and privacy. Clear glass visually connects the rooms, while frosting blocks sightlines.
• Large residential windows: Choose PDLC for privacy. For west-facing sunlight, heat, and glare, focus on SPD, EC, and other solar-control options.
• Office conference rooms: PDLC can replace some glass-and-blind combinations and connect to room controls, frosting at the start of a meeting and clearing afterward.
• Hospitals: Smooth glass is easy to wipe down and reduces the burden of dusty curtains, laundering, and mechanical-part maintenance. It suits privacy partitions that need frequent cleaning.
• Hotels: Switchable partitions can adjust openness and privacy between bathrooms and bedrooms, in presidential suites, spas, and pool areas.
• Storefront windows: With a projector, PDLC serves as either a clear display window or a frosted projection screen.
• Panoramic car roofs: SPD, AGC Digital Curtain, and related systems darken or switch to a shading state in strong sunlight, improving lighting and privacy according to the vehicle design.
• Office curtain walls: EC, SPD, and eyrise solar-control products address solar heat gain, HVAC energy use, glare, automation, and preservation of the view.

From optical performance to the complete quote

1. Visible light transmission (VLT): Check both clear and darkest states to understand the daylight range.
2. Haze: Clear-state haze is especially important for PDLC. Lower values generally look more natural; about 2%–3% is a useful benchmark for good performance.
3. SHGC / g-value: Use these to compare solar heat gain control rather than relying on broad claims of high heat rejection.
4. Infrared (IR) blocking: Check infrared performance and the wavelength range used in testing.
5. Ultraviolet (UV) blocking: High-quality products often reach around 99%; verify the specific model.
6. Switching speed: PDLC typically switches in milliseconds, SPD in seconds, and EC in minutes.
7. Power consumption: Check W/m² alongside glass area and daily powered hours.
8. Maximum dimensions: Pay particular attention to film width to avoid unexpected seams across a large pane.
9. Operating voltage: Confirm compatibility among the glass, transformer, and control equipment.
10. Outdoor rating: Confirm whether the product is intended for indoor or outdoor use.
11. Operating temperature: Make sure the range covers the local climate and actual application.
12. Continuous-power life: Understand the test conditions and long-term performance when kept clear.
13. Switching cycles: Assess suitability for frequent switching in meeting rooms or public spaces.
14. Warranty: Clarify duration, covered components, and repair responsibilities.
15. Edge sealing: Check treatment of humid environments, film edges, and electrical connections.
16. Controller: Verify features, compatibility, and replacement availability.
17. Smart home / BMS support: Confirm supported systems, interfaces, and additional equipment.
18. Glass breakage safety rating: Check safety requirements for the location and use.
19. Glazing construction: Confirm availability of tempered, laminated, or insulated configurations.
20. Quote scope: Specifically check whether controllers, transformers, wiring, and installation are included in the total.

The same per-square-meter price might cover a sheet of film, a finished pane, or an installed system. Meaningful comparisons start with a clear scope of supply.

Choose by project stage and primary purpose

Four Changes You Can See in Everyday Life

The most tangible smart glass applications fall into four groups: PDLC partitions that quickly turn from clear to frosted; electrochromic windows that automatically darken in sunlight and reduce reliance on shades; automotive glass that improves passenger comfort; and storefronts that combine clear displays with projection. They bring practical changes to privacy, building daylighting, travel, and retail presentation.

Glass is gaining other functions, too. Transparent displays can show ads, text, and video in storefront windows. Power-generating glass, heated deicing glass, antenna glass, and AR display glazing incorporate energy, temperature control, communications, and displays into the material. These go beyond dimming, turning windows into electronic components of buildings and vehicles.