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Smart film — also sold as smart glass film, PDLC film, or switchable privacy film — is an electrical product as much as it is a film. It runs on a controller, it draws power, and its data sheet reads more like an electrical spec than a tint spec. This post walks through the physics, teaches you to read the numbers a manufacturer actually publishes, and lays out what the install itself involves — wiring, panel limits and all — before you sign off on a run.
Published September 14, 2026 · Armored Glass Solutions
What It Actually Is
PDLC stands for polymer-dispersed liquid crystal, and that name is a fair description of what's actually in the film. Peer-reviewed research published in the journal Polymers describes a typical PDLC film as composed of micro- or nano-sized liquid-crystal droplets randomly dispersed in a continuous polymer matrix, formed through a process called phase separation. Gauzy, one of the manufacturers whose products we install, describes its own film the same way in its guide specification: a "Polymer-Dispersed Liquid Crystal (PDLC) sheet, composed of polymer matrix and liquid crystals."
That construction is the whole reason smart film behaves differently from every other film on our site. Solar film, security film and decorative film all do their job passively, with no ongoing input, once they're installed. Smart film needs a live electric field to switch states, which means every run needs a controller, a power source, and wiring back to both — before anyone ever asks about haze or clarity. We sell and install both Gauzy and GhostGlass PDLC smart film, and the rest of this post isn't about picking a winner between the two — it's about teaching you to read either one's data sheet before it goes on a wall.
The Physics
With no electric field applied, the liquid-crystal droplets inside the polymer matrix sit in random orientations. Their refractive index doesn't match the surrounding polymer's, and that mismatch scatters light in every direction rather than absorbing it — which is why the off-state looks milky or frosted white instead of dark. Apply a field, and the droplets' liquid-crystal molecules reorient so their refractive index lines up with the polymer's; light passes through with far less scattering, and the panel reads as clear glass again. Polytronix, another PDLC manufacturer, describes the same mechanism in plainer terms: "the droplet formations react in a synchronized manner allowing the liquid crystals to transition from opaque to clear."
Gauzy's own HP-LCG spec sheet illustrates that mechanism with two different transmittance numbers most people never see, because they get flattened into a single "VLT" figure. At its 42VAC configuration, Gauzy publishes a "Parallel Light Transmittance" of 4.8% off and 78% on, alongside a separate "VLT (Total Transmittance)" figure of 62.8% off and 80% on. Those aren't two measurements of the same thing: total transmittance counts scattered light along with direct light, while parallel transmittance counts only the light that passes straight through, undiffused. That gap is exactly why the off-state still has 62.8% of light passing through it in some direction even though almost none of it — 4.8% — is going straight through. It's diffusing the view, not blocking the light.
That same physics explains something worth knowing before you buy on the privacy pitch alone: because the film works by scattering light symmetrically rather than by reflecting more light back on one side than the other, there's no reason built into the mechanism for it to behave differently after dark. That's reasoning from how PDLC works, not a manufacturer's tested nighttime claim — nobody publishes a "works at night" spec. It's also the opposite mechanism from reflective "one-way" film, which we cover in a separate post on why one-way film reverses at night: that film depends entirely on which side of the glass is brighter, so it can flip once interior lights come on. A scattering film like smart film in its opaque state isn't relying on a brightness contrast at all, so there's nothing for the dark to undo.
Read The Data Sheet
A useful PDLC data sheet gives you at least four numbers: haze in the clear state, transmittance in both states, UV blocking, and switching time in both directions. The trap is treating any one of those as "the" number for PDLC film in general. It isn't — it's specific to one product line, on one document, tested under stated conditions.
Gauzy is the clearest example, because we could check it against three of its own published documents. Its current flagship HP-LCG spec sheet gives clear-state haze of 2.2% at its standard 70VAC drive and 3.3% at 42VAC, tested on a BYK "haze-gard i" instrument, indoors at 25°C. Its older CSI guide-spec document states a flat 2.5% haze figure instead — a different figure, for what looks like an earlier film configuration. Thickness tells the same story: the current HP-LCG sheet states 370 microns, the older CSI document states 350 microns, and Gauzy's own product page separately lists 560 microns for what appears to be a different, adhesive-retrofit SKU. Three documents, three thickness numbers, all from the same manufacturer. That's not sloppiness on Gauzy's part — it's product-line specificity that a shopper has to account for.
The lesson holds across the category, not just at Gauzy: always ask for the sheet for the exact product being quoted, not a general "PDLC film" spec sheet found elsewhere. Here's how the numbers we could verify compare across four manufacturers, shown to illustrate what each metric means — not to rank one product against another, since test conditions differ where the sheet says so:
| Metric | Gauzy (across its published documents) | Polytronix (Polyvision) | Intelligent Glass | GhostGlass |
|---|---|---|---|---|
| Drive voltage | 42–70VAC, true square wave, 25/32/50Hz | not published | AC 48–65V | ~60VAC |
| Power draw | 1–3 W/m² | 0.5 W/ft² (≈5.4 W/m²) | 5 W/m², 0.1A/m² | not published |
| Clear-state haze | 2.2% @70VAC / 3.3% @42VAC (haze-gard i, indoor 25°C) | not numerically published | not published | not published |
| VLT clear / opaque | Total: 80% / 62.8%; Parallel: 78% / 4.8% | ~75% clear / 96% blocked opaque | not published | not published |
| UV blocking | ≥99% | >99% | not stated on this sheet | ~99% (site claim, not a datasheet figure) |
| Switching time | 10ms off→on / 150ms on→off | "milliseconds," no figure given | not published | describes transition as "instant," no figure given |
| Thickness | 370µ (current) / 350µ (older doc) / 560µm (adhesive SKU) | not published | not published | not published |
| Max panel size | 1500mm width (film); 70in width (laminated glass, butt-joint above) | not published | up to 1.5m x 4m | not published |
| Warranty | 1-yr (film) / 2-yr (laminated glass) | not published | not published | 5-yr film / 3-yr power supply |
| Rear-projection use | not claimed on pages checked | not claimed | explicitly claimed, 4K/HD | not claimed |
Figures as published on each manufacturer's own data sheets or product pages, illustrating the metrics rather than ranking one product against another. Rear-projection support is a claim we could confirm on Intelligent Glass's published datasheet only — it isn't a general PDLC feature, and Gauzy's and GhostGlass's own pages don't make it for their standard privacy film.
The Electrical Side
Every manufacturer with a published drive voltage runs on AC, not DC: Gauzy at 42–70VAC, Intelligent Glass at 48–65VAC, GhostGlass at roughly 60VAC. Gauzy's guide spec gets specific about what the controller has to do with that voltage — it "must employ a 42VAC – 70VAC true square wave output," has to "stairstep up the voltage... and regulate the voltage so as to not create a high electrical transient pulse," and needs an "overvoltage protection circuit." On the line side, Gauzy's own instructions call for "110-240 VAC, 60 Hz electricity... supplied from a minimum 15A GFI circuit (20A dedicated circuit recommended)," and state plainly, "Do not connect more than 18 panels to each 20A circuit."
That's a real electrical scope, not an incidental detail, and both makers say so themselves: Gauzy's installation instructions state that "Connection to the power grid to be performed by a qualified electrical professional engineer," and GhostGlass's own site states that "electrical work should be completed by a licensed electrician." We couldn't independently verify a specific electrical-code voltage or power threshold for this class of circuit against a primary code source, so we're not going to cite one here — the two facts worth remembering are the published drive-voltage range and the fact that the manufacturer itself calls for licensed or professional electrical work on the mains side, every time.
It isn't always a blunt on/off circuit, either. Gauzy's guide spec calls for a controller with a documented "DIMM function" and a 0-10V dimming option, and its current HP-LCG sheet lists supported operating modes as "Fade, ON/OFF, Dimming," with named controller options such as "DUO Mini & Flex" and "Multiplex." If dimming matters for a given room, that's a question for the specific controller being quoted, not an assumption to make on your own.
Power And Speed
Published power draw varies by maker: Gauzy states 1–3 W/m² ("on average 3 Watt/m²" on its product page), Intelligent Glass states 5 W/m² at 0.1A/m², and Polytronix states 0.5 watts per square foot, which works out to roughly 5.4 W/m². GhostGlass doesn't publish a numeric power figure on the pages we could review. No maker states a bare "0W when off" spec, but it follows directly from the mechanism covered above: with no field applied, there's no current driving the liquid crystals to align, so draw when opaque is effectively nothing — that's reasoning from the physics, not a manufacturer-quoted number.
Switching speed is the number most worth double-checking against the actual sheet rather than the marketing copy, because it isn't symmetrical. Gauzy is the only maker in our sources publishing figures in both directions: about 10 milliseconds to switch clear, and about 150 milliseconds to switch back to its opaque, private state. That second number matters — 150ms is still fast, but it's fifteen times the switch-to-clear figure, and it's the direction that makes the room private. Polytronix describes its switching qualitatively, as happening in "milliseconds," without a number. GhostGlass's own site describes its transition as "instant," with an "Immediate transition" callout, but doesn't publish a millisecond figure to back that word up — which is itself a useful reminder to ask for the number, not the adjective, when speed matters to how a space will be used.
Two Ways To Wire It
Every data sheet we reviewed defaults to the same behavior, which we're calling "normal mode" here since none of the manufacturers brand it with a specific term: no power means opaque and scattering, meaning private; applying power switches it clear. That's not a manufacturer safety feature so much as a direct consequence of the mechanism itself — no field, no alignment, so the scattering that makes the panel look milky simply continues by default.
Reverse-mode film is a real product: at least one supplier's product page describes reverse-mode smart film as transparent with the power off — the opposite of standard PDLC — and pitches it for spaces where the clear state is wanted most of the time, since it draws no power while clear. We couldn't retrieve numeric haze, VLT, or switching specs for reverse-mode film from a primary source — the one spec table we found was an unreadable image — so if reverse mode is on the table for a project, ask directly for its numbers rather than assuming they match standard PDLC.
The Install
Busbars and wiring are part of the panel, not an afterthought. Gauzy's guide spec describes "copper busbar and electrical wiring connected to a controller," and its installation steps include one that reads "Busbars: Seal and apply mechanical protection." Busbar position is itself a customizable, factory-set parameter on Gauzy's current HP-LCG sheet.
Panels come with size limits, and oversized openings get handled with a butt joint rather than a single sheet. Gauzy's film has a maximum width of 1500mm on its current sheet (with 1800mm listed as "coming soon"); its laminated-glass product tops out at 70 inches wide before requiring "two butt-jointed liquid crystal films laminated into a single panel." Intelligent Glass publishes a maximum size of up to 1.5m by 4m for its self-adhesive film. None of that is a trim-to-fit operation on-site: Gauzy's own "Cut-to-Fit" spec — covering custom sizes, shapes, busbar position, holes and notches — describes a fabrication-stage step that happens before the panel and its wiring arrive at the job, not something an installer cuts down after the fact. That's the same lesson our own Pasadena orthodontist project ran into directly: Gauzy switchable smart film across all 21 windows, with every panel custom-cut to its opening and wired. We wrote up what that job taught us about specifying PDLC in a working medical office in a separate post.
Moisture is its own line item, and the makers we reviewed are specific about it. Gauzy's handling instructions say plainly, "Do not expose film to moisture," and its laminated-glass version for exterior or wet-interior use has to be "wet-sealed and impervious to moisture with provisions to allow for weeping of condensation," with electrical connections required to "exit at the head conditions of any framing system in wet environment applications." GhostGlass states that "protecting the edges of the film from moisture is essential for long-term performance," and specifies a dry-apply installation only — its own instructions say it "should not be installed using water, slip solution, or wet application methods," which rules out the standard wet-slip technique used for most tint. Any bathroom, spa, or other wet-room application is worth flagging to your installer before the panel is even fabricated, not after.
Where It Fits
None of the above makes smart film a bad product — it makes it a product with real ongoing requirements attached to a real, on-demand capability that no passive film can match: the same pane of glass going from open and clear to private, electrically, on command. That's worth the wiring in a lot of rooms — conference rooms, treatment rooms, storefronts that want to change character at different hours.
But plain frost or decorative film is the better tool when what you actually need is a static, always-private (or always-diffused) piece of glass, with no ongoing failure mode to explain to whoever owns the building. Frost and decorative finishes, covered on our own decorative film page, need no controller, no power, and no electrician on the circuit — the tradeoff is that they don't turn back to clear on command. If the actual problem is narrower than a whole room — a screen or terminal that's readable from outside rather than the space itself needing to go private — our cloaking film page covers that specific, smaller job. Deciding between all three is exactly the kind of question worth putting to whoever's quoting the job, alongside the general questions we cover in what to ask a window film installer.
Before You Sign Off
Because so much of what determines whether a smart film install goes smoothly lives in the electrical scope rather than the film itself, these are the questions worth putting to whoever's quoting the job, sheet in hand:
Questions
UV, generally yes — most makers we reviewed publish 99% or better UV blocking: Gauzy states not less than 99%, Polytronix states greater than 99%, and GhostGlass states approximately 99% on its site. Solar heat is a different story. The standard privacy PDLC data sheets we checked don't make a heat-blocking claim at all. The infrared and temperature-reduction figures that do exist belong to a separate Gauzy solar-film product line, not the standard switchable-privacy film this post is about.
In normal mode, which is the default across every data sheet we checked, no power means no electric field, and no field means the liquid-crystal droplets stay randomly oriented and keep scattering light — so the glass reverts to its opaque, private-looking state. That's a direct consequence of the mechanism, not a manufacturer-branded safety feature. Reverse-mode film exists and does the opposite, defaulting clear with no power, but we couldn't find published numeric specs for it from a primary source, so we won't guess at how it performs.
At least for Gauzy, dimming is a real, published feature — its guide specs call for a controller with a dimming function and a 0-10V option, and its current HP-LCG spec sheet lists Fade, ON/OFF and Dimming as supported operating modes. That's a manufacturer-stated capability, not a universal claim for every PDLC product on the market.
Gauzy states an expected life of "over 10 years" for its film, provided it's installed by a Gauzy-certified installer and properly maintained, backed by a 1-year warranty on the film and a 2-year warranty on its laminated-glass version. GhostGlass separately publishes a 5-year warranty on its film and a 3-year warranty on its power supplies. Warranty and expected-life figures are specific to each maker and each product line — don't average them into one number.
Not according to any manufacturer we reviewed. Gauzy calls its custom sizing option "Cut-to-Fit," and it covers custom sizes, shapes, busbar position, holes and notches — but that happens at the fabrication stage, before the panel and its busbars are finished, not as something an installer trims after the material arrives on-site.
Sources
Keep Reading
Switchable PDLC film that goes private on demand — what it is, how it's wired, and what to ask before you spec it.
Read more →Frost, gradient and dichroic finishes that obscure a view day and night, with no controller and no power required.
Read more →Why reflective privacy film reverses after dark, and how that mechanism differs from a scattering film like PDLC.
Read the post →Free in-person site assessment anywhere in LA or Orange County. We'll look at your glass, your panel layout and your electrical scope, and spec the run against the actual data sheet — not a marketing page.