Side by side
| Smart film | Smart glass | |
|---|---|---|
| What it is | Adhesive film on existing glass | New glass panel with the layer inside |
| Published cost | $30 to $45 per sq ft for film [1]; $75 to $175 installed in LA [6] | $50 to $150 per sq ft installed [1] |
| Lifespan (HomeGuide) | 10 to 20 years [2] | 20 to 30 years [2] |
| Install | Applied like window tint, plus wiring [2] | Installed like regular glass, plus a power connection [2] |
| Best for | Retrofits, existing partitions and windows | New builds, remodels, wet areas |
HomeGuide says film is more cost-effective, especially for smaller jobs, but has a shorter life. UV, temperature changes, and humidity can make film peel, and scratched or uneven glass can make it look distorted [2]. The LA installer says factory smart glass can cost 2 to 4 times as much as a film retrofit in an existing building [6].
How PDLC works
PDLC stands for polymer dispersed liquid crystal. When powered, the crystals line up and the glass turns clear. With the power off, they scatter light and the glass looks frosted [4]. One maker's film switches in well under a second and is rated for over 800,000 switches [4].
With standard PDLC, the glass goes private if the power fails [4]. Some makers sell a "reverse" film that stays clear without power and turns private only when switched on [4]. In the frosted state, most daylight still comes through [3][4].
Other kinds of smart glass
Not every smart glass gives privacy. HomeAdvisor says PDLC is the only type that turns fully opaque [1].
- SPD (suspended particle device). Adjusts how dark the glass is, but doesn't give full privacy [1].
- Electrochromic. Tints gradually over a few minutes and holds its setting without constant power [1]. Berkeley Lab says it typically changes light transmission from 10% to 70% [5]. Its simulations found that smart windows with lighting controls in dry, sunny climates can use 30 to 40% less energy than regular windows [5]. That's for sun control, not bathroom privacy.
- Photochromic and thermochromic. React to sun or heat by themselves, with no switch [2].
Which should you choose?
Choose smart film if your glass is in good shape and you want privacy at a lower cost. Choose smart glass if you're replacing glass anyway, if the area is wet or very sunny, or if you want the longest life. Choose electrochromic if your goal is glare and heat control rather than privacy.
FAQ
Does smart film work on any glass?
It needs clean, smooth glass. HomeGuide warns that thin glass, scratches, or uneven areas can keep film from sticking properly and make it look distorted [2]. An installer should check your glass before quoting.
Does smart film block heat like window tint?
Only partly. One maker says its film blocks 12% of infrared heat when clear and 73% when frosted [3]. The LA installer says it doesn't match dedicated solar control film [6].
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