Electrochromic & Switchable Glass

Ask ten professionals and you’ll get two definitions. The precise one: electrochromic glass is a specific technology whose tint shifts gradually under a low voltage and holds without continuous power. The working one, heard far more often: "electrochromic" as shorthand for any electrically switchable glass or film — the kind that turns from clear to private on command. Both are useful, as long as you know which you’re dealing with. Most enquiries that arrive under the word "electrochromic" are, in substance, about switchable film and switchable glass — instant, on-demand privacy — rather than the specific electrochromic technology. So that’s where this page starts.

For the majority of projects, switchable glass means PDLC or PNLC. These switch between clear and opaque instantly: transparent one moment, a solid privacy surface the next, with a single control. PDLC is opaque at rest and turns clear when powered; PNLC is the reverse — clear at rest, opaque when powered. Their real advantage is flexibility: switchable film can be applied to glass that’s already installed, as a retrofit made on site, or laminated inside new glass for a finished, sealed unit. That makes them the natural answer whenever the brief is privacy on demand: meeting rooms, clinics, shopfronts, partitions, homes. Where the switched surface should read as a deep, glossy black rather than a frosted one, Blackout Hyper Glass takes the same switchable idea toward concealment and aesthetics — a glossy black surface at rest that becomes a smoky transparent when powered.

SPD acts on colour: it dims across a continuous range of tint levels, from full clarity to a deep dark shade, without ever closing the view. It’s driven continuously to hold a level and is built to follow the sun through the day — the right fit where you want graduated control of light and glare rather than a privacy screen.

Used precisely, electrochromic glass is one specialised member of the family, with a different job from the switchable films above. It doesn’t switch to opaque — it tints. A low voltage shifts it gradually from clear to a deeper shade to manage the sun’s light and heat, and even at its deepest tint the glass stays see-through: you keep the view while glare and solar gain are cut back. It is solar control, not privacy. Two things define it. It is bistable — power changes the tint, it doesn’t hold it, so the glass keeps a chosen state on its own with virtually no energy draw. And it is built into the glazing — laminated safety glass or an insulated glass unit, never an applied film. That makes it the choice for façades and high-efficiency buildings, where glass has to govern solar gain across the whole day.

On façades, skylights and large windows the family shows its range. Where the need is dynamic control of sun and glare with the view kept, electrochromic glass does the architectural, all-day job: it tints while staying transparent. Where it’s privacy and light control on interior glazing and partitions, switchable film and glass do the work. The same building, two different behaviours: the right one depends on whether you’re shading a view or creating privacy.

It depends which sense you mean — and this is where the umbrella term matters most. Electrochromic glass, in the strict sense, is not a film: it’s manufactured inside the glazing and arrives as finished glass or an IGU. But switchable film absolutely exists — PDLC and PNLC are made precisely as a film that can be applied to installed glass or laminated into new units. So if what you need is a switchable film for glazing you already have, the answer isn’t strict electrochromic; it’s switchable film.

Start from the behaviour you want, not the label. If it’s instant privacy — clear to opaque on command — switchable film or glass (PDLC, PNLC) is the answer, and it’s what most "electrochromic" enquiries resolve to. If it’s a black, concealing switched surface, Blackout Hyper Glass. If it’s graduated dimming of light and glare, SPD. If it’s passive solar control on a façade — the view kept, the state held without power — electrochromic glass. Being clear about these distinctions is how we help you specify once, correctly.