Drag slider across photo to show an example of window change – this can be adjusted between Clear and 100% tint or frosted effect.
Ever since the window was invented, mankind has sought to control the passage of light through it – using blinds, shutters or curtains. Anything to tame a blinding sun, or to shield from prying eyes.
Smart glass, or switchable glass (also known as smart windows and switchable windows), refers to a special type of glass that changes its light transmission properties when energy such as electricity, light or heat is applied.
When activated, smart glass changes from transparent to a translucent or opaque state, blocking some or all of the radiation. The major smart glass technologies include active technologies such as electrochromic, suspended particle, micro-blind, polarised shades, and liquid crystal devices, and passive technologies such as photochromic and thermochromic. Smart glass can save costs for heating, air-conditioning and lighting and avoid the expense of installing and maintaining motorised light screens or blinds or curtains. Most smart glass blocks ultraviolet light, reducing fabric fading; for SPD-type smart glass, this is achieved in conjunction with low emissivity coatings.
Critical aspects of smart glass acceptance in the market include material costs, installation costs, electricity costs and durability, as well as functional features such as the speed of control, possibilities for dimming, and the degree of transparency.
The inventions of a variety of smart glass systems over the last few decades have offered exciting technological improvements over the traditional methods of dressing windows. But they have failed to achieve significant take up in the market, mainly because of cost. Other inhibiting factors are:
- Need to use electricity – all active systems currently depend on this
- Durability and ageing – reports of systems failing or badly degrading after 2 – 3 years
- Speed of change from clear to opaque/translucent
- Speed of transition – some systems are too slow to respond
The manufacturing processes to make most smart glass are relatively complex and expensive – to a degree that only very specialised or exclusive applications can justify the cost (typically of the order of £1,000 per square meter, depending on application and volume).
The world flat glass market is estimated to be 63 million metric tons of glass, worth some £23 billion in 2014, with an annual growth of 5%.
The global market for smart glass products is forecast to be £2.6 billion by 2016 with an annual growth rate of 21.6%. (Source: BCC Research http://www.bccresearch.com/market-research/advanced-materials/smart-glass-technology-global-markets-avm065b.html).
There is clearly an opportunity for a smart glass product that can break the cost barrier.