PDLC vs Electrochromic vs SPD: Which Switchable Glass Technology Fits Your Project?
Three switchable glazing technologies, three very different cost and behavior profiles. A practical selection guide for architects and buyers.
See the film switch
An SGV install switching between transparent and frosted - the film this article talks about.
- Under 0.1 s switching - clear to frosted the instant power changes
- ~5 W per m² - less power than a light bulb, only while clear
- Factory-cut to size - busbar finished and tested, ready to wire
When specifiers search for "smart glass" they find three competing technologies: PDLC, electrochromic (EC) and suspended particle device (SPD). They all change how light passes through glass, but they behave very differently - and picking the wrong one usually shows up as a cost overrun or a disappointed client. Here is the practical comparison.
The one-line summary
- PDLC - instant privacy switching, lowest cost, frosted-not-tinted. The choice for interiors: partitions, bathrooms, clinics, hotels.
- Electrochromic - slow tinting, memory without power, highest cost. The choice for whole-facade solar control on new buildings.
- SPD - fast tinting with precise level control, but needs high drive voltage and carries a premium price.
How they differ where it matters
| Criteria | PDLC film / glass | Electrochromic | SPD |
|---|---|---|---|
| Switching speed | < 10 ms - effectively instant | seconds to minutes | 1-3 seconds |
| Off state | milky frosted | tinted (remembers state) | dark tinted |
| Privacy | complete - blocks direct view | partial - view remains visible | partial |
| Drive voltage | AC 48-65V, safe low voltage | low-voltage DC | 110-220V drive |
| Cost level | lowest | highest | high |
| Typical use | interior partitions, bathrooms, retrofit film | curtain walls, skylights | auto windows, marine |
Why PDLC wins inside buildings
For most interior projects the deciding factors are privacy and speed. PDLC is the only one of the three that blocks direct view completely - and it does so instantly, on safe 60V power, at the lowest cost per square meter. The frosted state doubles as a projection surface, and self-adhesive versions retrofit onto existing glass without any demolition. That is why PDLC dominates office partitions, hotel bathrooms, clinic glazing and residential retrofits worldwide.
When to specify EC or SPD instead
Choose electrochromic when the goal is solar heat control across a large facade and the glass can transition slowly; its memory state without power suits big curtain walls. SPD suits automotive and marine glazing where fast, continuously variable tinting matters and the higher drive voltage is engineered in from the start.
Check the datasheet, then check the factory
Whatever the technology, ask suppliers for the full indicator table - on/off transmittance, haze, UV/IR blocking, switch-cycle life and warranty. Our PDLC and PNLC datasheets list every figure, and all spec sheets are free to download. Unsure which fits your project? Send us the application - we will tell you honestly if PDLC is not the right answer.
Talk to an engineer
Send your dimensions and application - itemized quote within 24 hours.
