How Does Switchable Glass Actually Work?

The Technology in Plain English

Switchable glass — also called smart glass, privacy glass, or PDLC glass — changes from transparent to opaque at the flick of a switch. No moving parts, no mechanical blinds, no curtains. Just glass that turns milky white in an instant.

But how? The answer is surprisingly elegant.

PDLC: The Science Behind the Magic

PDLC stands for Polymer Dispersed Liquid Crystal. Here's how it works in simple terms:

1. A thin film containing millions of tiny liquid crystal droplets is sandwiched between two layers of glass (or applied as a self-adhesive film to existing glass)
2. When no power is supplied, the liquid crystals are randomly scattered, causing light to diffuse in all directions. The glass appears frosted/opaque. You can't see through it.
3. When electricity is applied (typically 65-110V AC via a transformer connected to a standard power supply), the crystals align in neat rows, allowing light to pass straight through. The glass becomes transparent.

The switching happens in milliseconds — it's virtually instantaneous. And there are no moving parts to wear out.

Power and Running Costs

One of the most common questions we get is about energy consumption. The good news:

• Switchable glass uses approximately 5-7 watts per square metre when transparent
• That's less than a standard LED light bulb for a typical meeting room partition
• When opaque (off), it uses zero electricity
• A standard transformer connects to a regular 240V mains supply

The Four Types We Supply

1. Regular Switchable Glass

The standard option. Opaque when off, transparent when powered. Ideal for meeting rooms, healthcare partitions, and any space where privacy is the default state.

2. Reverse Switchable Glass

Transparent when off, opaque when powered. Best for spaces that are usually open but occasionally need privacy — like executive offices or reception areas.

3. Blackout Switchable Glass

Goes completely dark when switched, blocking all light transmission. Designed for AV rooms, home cinemas, presentation suites, and hotel bedrooms where total darkness is needed.

4. Solar Control Switchable Glass

Combines privacy switching with solar heat rejection. Reduces solar gain while maintaining the ability to switch between transparent and opaque. Ideal for south-facing facades and conservatories.

Laminated Glass vs Retrofit Film

There are two ways to get switchable glass into your project:

Laminated Units (New Build)

The PDLC film is permanently laminated between two panes of glass during manufacturing. This creates a robust, long-lasting unit that can be cut to custom shapes and sizes. Best for new-build projects or full refurbishments.

Self-Adhesive Film (Retrofit)

A switchable film is applied to the surface of existing glass, much like a window tint. This is significantly cheaper and faster to install, making it ideal for refurbishment projects where replacing the glass isn't practical or budget-friendly.

Lifespan and Durability

• Switching cycles: 100,000+ (that's switching on and off roughly 14 times a day for 20 years)
• Expected lifespan: 20+ years for laminated units
• UV stability: Modern PDLC films are UV-stabilised to prevent yellowing
• Maintenance: Clean like normal glass — no special products needed

Related Products

View Our Switchable Glass Range →