If you're considering installing smart glass, one of the first concerns that comes up is surprisingly simple: does it use electricity, and if it does, how much is it actually going to cost you?
The short answer is yes — smart glass does use electricity — but not in the way most people expect. The reality is far more nuanced, and once you understand how the technology works, the energy cost becomes far less intimidating than it first appears.
At the centre of most modern switchable smart glass systems is PDLC "polymer dispersed liquid crystal" technology, which relies on an electrical current to control how light passes through the glass. When power is applied, the liquid crystal molecules align, allowing light to pass through and making the glass transparent. When the power is turned off, those same crystals scatter randomly, diffusing light and creating a frosted or private effect.
This means something very important: smart glass only actively uses electricity when it is in its clear state. When switched off, it does not require power to remain opaque. In practical terms, this is the opposite of what many people assume. Instead of constantly consuming energy, the system only draws power when you want visibility.
Smart glass only requires power when in transparent mode. When set to opaque (frosted), the glass maintains privacy without any electrical consumption. This makes it one of the most energy-efficient privacy solutions available.
In real-world applications, smart glass is extremely low power. Typical PDLC systems consume around 5 to 8 watts per square metre when active. To put that into perspective, that is roughly equivalent to a small LED light bulb spread across an entire square metre of glass. Even larger installations remain relatively efficient because the power requirement scales with surface area but remains low per unit.
Another way to understand this is through usage over time. Some data suggests that a square metre of smart glass might use around 1 kWh after roughly 200 hours of continuous operation, which is a very modest level of consumption. For a typical home installation, even with multiple panels, the energy usage is unlikely to make a noticeable difference on your electricity bill unless the glass is left in transparent mode continuously.
There is also a brief spike in power usage when the glass switches between states, but this only lasts for a fraction of a second and has almost no impact on overall energy consumption.
What often gets overlooked is that smart glass is not just an energy consumer — it can also contribute to energy savings.
Because intelligent glass can control how much light and heat enters a space, it can reduce reliance on artificial lighting and air conditioning. In bright conditions, allowing more natural light into a room reduces the need for electric lighting. At the same time, managing solar gain can help prevent overheating, which reduces the load on cooling systems. Research and industry data show that smart glass systems can contribute to improved energy efficiency in buildings by managing light and temperature more dynamically.
This creates an interesting balance. While the glass itself uses a small amount of electricity, it can indirectly reduce larger energy costs elsewhere in the home or building. In many cases, the net effect is either neutral or slightly positive in terms of overall energy efficiency, especially in spaces with large glass surfaces exposed to sunlight.
There is also an important behavioural factor. The actual cost of running smart glass depends heavily on how it is used. If the glass is left in transparent mode all day, it will consume more electricity than if it is used intermittently. However, even in constant use scenarios, the low wattage means the cost remains minimal compared to most household appliances.
To give a realistic example, imagine a home with 5 square metres of smart glass. At an average of around 5–7 watts per square metre, the total power draw would be roughly 25–35 watts when fully active. That is less than many standard light fixtures. Over the course of a day, the cost of running that system would be measured in pennies rather than pounds.
Another factor to consider is that smart glass systems require supporting electrical components, such as transformers, controllers, and wiring. These ensure safe operation and consistent voltage supply but do not significantly increase ongoing energy consumption. They are part of the installation rather than a major contributor to running costs.
A common concern is whether smart glass could replace traditional window coverings like curtains or blinds entirely, and how that affects energy use. In many cases, it can. Because the glass itself controls privacy and light transmission, it removes the need for physical coverings that block light or trap heat inefficiently. This can actually improve how a space handles daylight and temperature, making it more energy-efficient overall when used correctly.
However, it is important to be realistic. Smart glass is not a replacement for insulation, and it does not eliminate energy bills. Its strength lies in control and optimisation rather than absolute energy reduction. It allows you to manage light, privacy, and heat in a way that traditional materials cannot, but it still operates within the broader energy dynamics of the building.
So, does smart glass use electricity? Yes — but very little. The technology relies on a low-voltage electrical current to function, and that energy is only required when the glass is in its transparent state. In return, it offers dynamic control over light and privacy, along with potential secondary energy savings through improved environmental management.
The more important question is not whether it uses electricity, but whether the energy it uses is justified by the functionality it provides. For most modern applications in 2026, the answer is clear: the cost of running smart glass is minimal, especially when compared to the level of control and flexibility it adds to a space.
In practical terms, it is one of the rare technologies where the perceived energy cost is far greater than the reality.
Everything you need to know about smart glass electricity consumption and energy costs.
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