A couple of articles regarding a new heat blocking film which blocks 70% of heat from the sun.
https://www.channelnews.com.au/air-conditioner-sales-under-threat-from-heat-blocking-film/
Sounds like the best thing since sliced bread.
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Dichroic films have been around for quite a while. I would be interested to know what is so special about this one, or conversely, why have they not been used widely before. Price and durability are (at minimum) two attributes that need to be right before you have a practical solution.
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The heat rejecting properties of window films is limited to solar radiation only which is comprised of ~53% IR, ~44% visible light and ~3% UV. It does little to nothing in preventing conducted heat from the ambient air outside or the heating effect on the glass itself. Films like this are only of benefit to windows facing full sun and will do next to nothing if the windows are already shaded.
I’m not sure I’d like that frosted white look in the third picture after only being subjected to the heat of somebody’s hand. It would spend most of its life being opaque if used in areas it was designed for, even at night.
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I think it is the almost transparent nature of the film until it reaches the temperature that leads to the change in the fibres. From my reading of the article they especially looked at the IR blocking/rejecting capability of the film to achieve the savings. They see this as an improvement over the use of other “Smart Windows” re this quote ““Smart windows on the market currently are either not very efficient in rejecting heat from the sun, or, like some electrochromic windows, they may need more power to drive them, so you would be paying to basically turn windows opaque,” Fang says.”
I am not sure use of this film is about domestic usage but rather in the large buildings such as offices and towers which are mostly in use during daylight hours and so of help in conserving AC and cooling costs in those hours.
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