There are variable answers to this question, largely due to the different evolutions of switchable film products that have been developed over the last 25 years.
Where your Switchglass™ is to be located, i.e. internally or externally, in direct or indirect sunlight, and how often it is in use, must also be taken into consideration.
Of significance too is the make-up and application of the electrical components, such as the busbar. If incorrectly applied, the silver paste used in its application will crack when exposed to UV rays, causing the Switchglass panel to fail prematurely. The silver paste is typically used for Panel Circuit Boards and is not designed to be used externally. The busbar’s wiring must also be anchored securely with specific materials to withstand movement during application and installation.
Another major component of Switchglass™ is its switchable film. Listed below are comparable film products available on the market.
Liquid Crystal (LC) Switchable Film Evolutions
US Patent 4435047 – Patent expired
Emulsion Technology or Nematic Curvilinear Aligned Phase (NCAP) Technology
PDLC – Polymer Dispersed Liquid Crystal
Utilises water soluble polyvinyl alcohol to disperse liquid crystal droplets
Utilises a non-linear polymer to disperse liquid crystal droplets
How Long Does Switchglass™ Last?
Let’s start with the assumption that the switchable film products listed are being laminated by qualified companies using quality products and that the longevity of each of the compared film products’ evolution is not compromised by this part of the process.
Evolutions 1 and 2
Invented over a quarter of a century ago, these LC switchable films have similar features. They should be laminated between glass to prevent absorption of moisture from the air. These products are recommended for internal use, but if used externally, would need to be double glazed into insulated glazing units (IGUs).
• If installed internally (no direct sunlight), used daily and for 50% of the time switched off and on, the laminated switchable films will last between 15-20 years.
• If installed for external use and the products have been double glazed using high quality soft coat low-e glass, used daily and for 50% of the time switched off and on, the laminated switchable films will last between 5-10 years.
• If installed internally (no direct sunlight), this product will last between 30-50 years. It can be left on permanently and does not require any switching off to prolong its life.
• If installed externally, this product will last between 20-30 years and does not need to be double glazed.
Over the years, many developments have improved the reliability of all three generations of LC switchable film and it would not be possible to come up with fixed rules that encompass the permutations or variances associated with these switchable film products.
In addition, pricing and quality fluctuate wildly due to the many different manufacturers associated with this technology.