Switchable glass is the thing people have seen in a hotel bathroom or a car advert and filed under expensive gadget. It is neither as exotic nor as universal as that suggests, and the useful conversation is about where it belongs rather than how clever it is.
So here is the mechanism, the running costs, and the honest list of rooms where we tell people not to bother.
The mechanism, briefly
The product is called PDLC, which stands for polymer dispersed liquid crystal. Inside a thin layer bonded to your glass sit millions of microscopic liquid crystal droplets suspended in a polymer.
With no power running through it, those droplets sit at random angles. Light entering the layer hits thousands of differently oriented crystals and scatters in every direction, so the pane reads as a solid milky white. You cannot see through it, but daylight still passes, which is the key difference from a blind.
Apply a low voltage current and the crystals all snap into alignment. Light passes straight through without scattering and the pane goes clear. Cut the power and they relax back to random within a fraction of a second.
That is the whole trick. Frosted is the resting state. Clear is the powered state.
What that means in practice
The resting state matters more than it sounds, and it is the first thing we explain when someone asks about a bedroom.
Because clear requires power, a switchable pane defaults to private. A blackout, a tripped breaker, a failed transformer, all of them leave you frosted rather than exposed. For a bathroom or a bedroom that is the correct way round, and it is a genuine argument for the product over anything motorised.
It also means clear glass has a running cost. The draw is small, roughly comparable to a low wattage bulb per square metre, but it is only drawing while clear. Most people use it the other way round from how they imagine, leaving it clear during the day and switching to private in the evening, which puts the consumption during daylight hours.
The wiring is the real project
This is where switchable jobs differ from every other kind of work we do, and where quotes from different companies stop being comparable.
PDLC runs on low voltage supplied through a transformer, and that transformer needs a feed and somewhere to live. On an interior partition with a wall cavity nearby, that is straightforward. On an existing exterior window in a finished room with no power on that wall, getting a supply to the frame is the bulk of the job, and it is the part a cheap quote quietly leaves out.
Where the work needs a licensed electrician, we bring one in and it goes in the quote at the start. The control side is flexible once the feed exists. A wall switch, a remote, or an app, and it can be tied into home automation if that is already in the house.
Ask anyone quoting you switchable glass exactly where the transformer goes and who is running the feed. If the answer is vague, the number is not real.
Where it earns its place
We recommend it in a fairly narrow set of situations, and it is excellent in all of them.
- A glass partition that needs to be both. Meeting rooms, consulting rooms, home offices. Open and connected most of the time, sealed off on demand, with no blind rattling on a glass wall.
- Ensuites and bathrooms with a view worth having. The room that most wants privacy is often the room with the best window. This is the only product that gives you both without a compromise.
- Bunkies, boathouse sleeping rooms and anything facing a dock. Nowhere sensible to mount a blind, and a permanent frost would waste the outlook.
- Rooms where night privacy is the actual requirement. A reflective covering reverses after dark. Switchable does not care about the time of day, because it is not working on a light difference.
Where we tell people not to
Plenty of enquiries end with us talking someone out of it, usually for one of these reasons.
- The problem is heat, not privacy. PDLC is not a solar control product. If your west-facing family room is unbearable at four o'clock, switchable glass will not fix it and solar control will, at a fraction of the price.
- The room only needs daytime privacy. A front room overlooked at lunchtime is a job for a dual reflective covering. Paying for switchable to solve a daylight-only problem is spending several times what the fix costs.
- The glass never needs to be clear. If a bathroom window is frosted permanently and nobody minds, a decorative frosted finish does the same job with no power, no wiring and no failure modes.
- The budget is fixed and the glass area is large. Switchable is priced by area and is the most expensive thing we install. On a big wall it can consume a budget that would have solved four rooms.
Living with it
The frosted state is a true white haze rather than a grey shade, and it looks deliberate. Clear is clear, with a very slight haze that most people stop noticing within a week and some never see at all. Look at the two photographs on our home page. That is one sliding door in Innisfil, shot in both states on the same afternoon, with no editing between them.
Switching is effectively instant. There is no motor, nothing mechanical, and nothing to collect dust in a slat.
Like everything else we fit, it goes onto the glass already in your frames. Nothing is torn out and no units are ordered from a factory, so a partition that would take weeks as a replacement is done in a day or two once the electrical side is sorted.
It is the best product we install. It is also the one we most often tell people they do not need, and both of those things are true at once.
