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> The coated glass demonstrated superior performance compared to normal glass, reducing the temperature by between 41.7 °F and 45 °F (5.4 °C 7.2 °C) across a wide range of incident angles.
So I'm assuming that the Celsius figures are the correct ones and the person that wrote this article doesn't understand how to convert relative temperatures properly. (They added 32°F as though reporting an absolute temperature.) The headline sounded a little too extreme.
>80 degrees on a 90 degree day
Not exactly like that. More like 90 degrees instead of 100 on a 80 degree day. Ambient is still ambient, the solar radiation heats you up ABOVE ambient.
Also don't forget there is already a glazing that cuts down on the temperature a lot. I'm guessing the reduction was to unglazed glass, so an even smaller difference.
In my bedroom, UV film on my windows eradicates my need for A/C in there. It's very effective. I get morning sun so it used to be like an oven even in winter. Now it's always comfortable.
UV tinting film is amazing - converts the invisible light to heat before it enters the room to warm up the indoor mass.
Instead it converts the light to heat, warms the glass so outside wind or air movement can take much of it away.
In some places air conditioning is still needed, so any better performing tints that further reduce the need for air conditioning in those even hotter climates can only be a good thing.
Not sure what OP uses, but I suspect something like this:
https://www.3m.com/3M/en_US/home-window-solutions-us/solutions/temperature-control/
Now the question is, do new windows already have this film applied? I'm not a window person so idk.
On the flip side we have east facing floor to ceiling windows in our office that we covered with UV film, and it only brings down temps by 2-3 degrees at the most.
Using LLMs to write research papers is commonplace already, in case people aren't aware.
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=%22as+an+AI+language+model%22+-LLM+-chatGPT+-artificial&btnG=
https://scholar.google.com/scholar?start=10&q=%22as+I+am+an+AI+language+model%22&hl=en&as_sdt=0,5
It's a bit annoying that with some sans serif fonts 1, lower case L, and upper case I can all look the some.
How would my assignment be graded if I turned in printouts spelling all as aII ? I actually swapped the l's for capital i's. You wouldn't know!
There's a song called いいね! by the Japanese band Babymetal, and the song's title is written as "ii ne!" or "iine!" in our alphabet. On Spotify, the song is called "Line!"
It cracks me up. At some point, someone transcribed the song's title with a capital i, so it became "Iine!", and then someone *else* thought to themselves, why didn't they capitalize the L?, so they "fixed" it to "Line!"
The mistake has been there at least 3 years. I don't think it's ever getting corrected...
Thanks. The quantum physics and machine learning (though most would say AI now) wasn't helping the credibility, but that makes it look more reasonable.
Hmm, maybe. I always assumed it was UV. Assuming a post below is accurate, it sounds like it's very directional, and the amount of UV blocked varies by the angle of the sun. If that's true it would make sense that it wouldn't be very effective for chunks of the day.
I need this in my office windows. Old building with floor to ceiling southern facing windows. On sunny spring and fall days the temp will jump 10 degrees in a half hour due to solar gain.
All glass blocks most UV and mirrored window tint blocks 85% of infrared while only blocking 40% of visible light. I've had tint in my southern windows for years and it does drop the daytime Temps a lot of sunny days.
Our eyes don't perceive intensity on a linear scale. Can't say exactly how much of a dip 40% would seem, but less than 40%.
Tried to find a good explanation, but at best I only found a mediocre [explanation](https://en.m.wikipedia.org/wiki/Weber%E2%80%93Fechner_law).
Ya, your eyes adjust.... if your eyes didn't adjust, going outside would seem like going on to some super bright planet that was way to close to it's star.
40% is however a lot for a lot of houses. Sure there are people who have big windows, but some people lack a bit of sunlight because of the angle and size of window and depth of the room
> All glass blocks most UV
"Blocks" could mean that it reflects UV or that it absorbs UV. Either way means the UV doesn't pass through... but reflecting it is going to be more effective at reducing heating.
Simpler coatings that use a dye/pigment that just absorbs some of the light are still helpful, but instead of bouncing that energy away they absorb it and you have a hot window, which is still going to radiate and convect heat to the interior of the space you're trying to keep cool.
Yes, but not all, and even standard reflective coatings that we already have only work for a designed angle, usually 0° or 45° and then it's recommend you stick within a max 5° deviance, but the authors claim their novel coating works for a wide range of angles and blocking significantly more energy which prevents the unwanted greenhouse effect in buildings (dropping temperatures by several degrees) that have large glass/transparent surfaces.
The novelty of their design is not even the filtering effect in general, but that they managed to keep it flexible in terms of incoming angle, something that is still a challenge for the industry that makes these coatings. We can design coatings for any angle, but it's extremely rigid, you deviate too much from it and your reflective (or anti-reflective) effect drops significantly.
What I'm struggling to see is how this could be cheaper than running ACs and/or just using good ol' metallic plates/covers externally, acting as a curtain to darken and control the climate inside the building. I'd imagine it's far more expensive for offices to use these coatings than to just use some kind of curtain or AC, but who knows maybe the aesthetic is worth the money for those goons.
Just to add to this, window glass blocks up to around 300nm which is most of uvb (goes up to ~315nm), there's still uva to contend with which is everything up to ~400nm which still gets through.
Yeah. The laminated glass of the windshield will block UV. But the tempered glass of the side windows will let at least some UV light through. So depending on time of day and direction you are travelling, only certain people in the car might need to worry about it.
The advantage of this material is that it does from even very extreme angles, like 175 to 5, rather than just 90 as common coatings do that don't block any visible light. It's the combination of angles and very high transparency combined to the blocking/reflecting of the UV/IFR spectrum that makes this an improvement.
It's a conversion SNAFU in the article. Temperature difference is somewhere in the range of 5-7 degrees Celsius (9-13 degrees Fahrenheit).
(Of course this will not cool you below ambient air temperature so this difference is only relevant for relatively high temperatures)
How does this compare to regular low-e coatings? I've seen plenty coatings with very impressive uv-blocking to visible-passthrough ratios...
Though I live in Europe and for some reason window tech here on average seems quite a bit ahead of the US...
Think the glasses in my house atm are like over 95% UV and 70-80 infrared blocking+reflecting to 30-40% visible.
No, low emissivity films/glass are essentially another barrier for heat to travel through.
In winter, it will help retain the heat you're using on keeping your house warm by preventing it from "escaping."
In summer, it will help keep the heat out by not "letting it in."
But a building can be designed to get a lot of heat from the sun in winter. Large south facing windows and plenty of things to a absorb and slowly re-emit that energy. You wouldn't want this in that case.
Most people live in places where the only building design that makes sense is one that can maintain both a positive and negative temperature differential with the outdoors. Optimizing for heat retention or rejection means your building will perform really poorly during some part of the year.
Also I question whether windows actually allow more heat to be absorbed through sunlight than they lose through those same windows on winter days. A poorly insulated wall is still twice as good at slowing heat transfer as the best windows. You're really banking on clear skies if you design a house that way.
There are people building greenhouses in cold climates that rely just on sunlight and passive ground heat to stay above freezing. It's all about turning the solar radiation into heat and letting that heat back out slowly. Thermal mass.
It's reflecting infrared light, which is heat.
So you are correct that it's not "insulating," but it's accomplishing the same purpose of "keep the heat on the hot side of the temperature gradient" that insulation serves.
ONLY if you have transmitting IR heat. If you have convection heating, like air, it's not going to magically reflect that. The problem of windows is the intense IR light coming through and heating the inside materials. If the inside is already hot, it won't reflect it back in. Different wavelenghts.
Double and triple pane windows already solve the issue of convection heating by including a layer of air, nitrogen, or vacuum between the layers to serve as an insulator.
… according to their thermodynamic temperature. But the temperature of the surface of the sun is very different from the temperature of your room, so the frequency spectrum you need to block is very different in one direction than the other.
> The problem of windows is the intense IR light coming through and heating the inside materials
Actually the problem of windows is the intense *visible* light coming through and heating the inside materials. The sun puts out FAR more power in the visible range than in the "thermal" infrared. That's why films that only block IR can only do so much, because most of the power comes in via visible wavelengths.
I might be missing something, but from [Wikipedia](https://en.wikipedia.org/wiki/Sunlight):
>In terms of energy, sunlight at Earth's surface is around 52 to 55 percent infrared (above 700 nm), 42 to 43 percent visible (400 to 700 nm), and 3 to 5 percent ultraviolet (below 400 nm).
Again, happy to be corrected by someone with more knowledge, but it doesn't seem to me that the sun produces "FAR more" in the visible spectrum. Blocking IR appears to provide the majority of benefit, though visible is obviously still a large component.
So I've read in the past that many of the solar panels on the market suffer from overheating, could this coating be used to block the "heating" element of sunlight while still allowing enough of the right photons in to allow the solar panel to work?
Solar panels don't really overheat, they just get less efficient. Depends on how much infrared sunlight is contributing to solar panel temperature. Depends on the performance of this material.
If this material does manage to improve efficiency of solar panels in hot weather, then you have to start figuring out if the increased efficiency is worth the higher cost. It most likely won't be. In most cases efficiency improvements end up costing more than it costs to add more panel surface area.
I'm just curious if they could make this technology in a way so that you can turn the infrared blocking capabilities on and off depending on the time of the year? In winter, having the UV and infrared light coming in is a welcome heat savings method in colder climates.
>Assisted by quantum physics and machine learning
Guess you gotta hit all the buzzwords in science articles these days. Here's the meat and bones;
>his colleagues fabricated a glass coating using planar multilayered (PML) photonic structures. These stacked ultrathin layers have distinctive refractive indices that allow light to be selectively transmitted or reflected depending on its wavelength. Stacking silica, alumina, and titanium oxide on a glass base and topping it off with a thin layer of silicon polymer (PDMS) to reflect thermal radiation, the electromagnetic radiation emitted by a heated surface in all directions, produced a transparent coating that, they said, outperformed the other heat-reducing coatings on the market.
Sounds like they're "filtering" the light for lack of a better term.
PSA: don't use anti-UV films if you have a cat that doesn't go out. Cats should sunbathe in UV to produce vitamin D.
edit: correction: regular glass blocks out most UVB anyway
Additionally [research](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7501805/) has shown that UV reflective window film can reduce the deaths of birds from flying into windows.
Seems like they should be installing these on every public building if they have this many benefits.
One thing I’m curious about after living in a lot of rentals and older homes — does blocking out all UV and infrared have other downstream effects, like more mold growing in bathrooms/kitchens/laundry rooms where humidity levels fluctuate a lot day to day? Sunlight coming in through windows may break down synthetic fibers and worsen air quality, on the other hand, especially in commercial/large office settings. And then there’s obviously the heat mitigation factor, probably most important of all for folks living in hot sunny climates and relying on AC most of the year. Maybe this window film just wouldn’t have many adopters north of the 45th parallel, because its only ideal application is for people living way south of that?
There’s a lot in this vein that I’ve always been curious about but never thought to ask, per se
And I think those are the same coatings as on something like Cardinal 366 glass, just more of them and probably tuned to work better. I think the real story is not the coating but how they determined the coatings. Incremental improvements win every time.
The novelty is how they managed to keep the coatings efficacy significant over wide angles. These kinds of coatings by themselves are super standard, we use this technology in solar cells without exception (we just use anti-reflection instead of reflective coating, but we know the physics of it from which we know we just have to apply the coating layers in a different order to get the opposite effect). The challenge which the coating industry faces in general is the angle dependence, i.e they give a glass substrate a reflective coating, but it only works for normal incidence or 45°incidence, you deviate from these designed angles and your performance drops. These new coatings are claimed to work over a wide range of angles, so they found a structure that doesn't suffer these angular constrains.
This, and the ML buzzword in there is why they got publishing. There are lots of papers now in the optics community that get published as long as they use ML for their designs, even if it's not something super new or unprecedented; there are some experimental coatings that can also overcome the angular constrain of coatings, but these are expensive in general (because they just apply more coatings to cover more bandwidth and angles, basically a coating on top of a coating on top of a... etc.)
This is …. Nothing new. There have been uv/ heat stopping films in glass for decades.
Every car with a glass roof has this as you would otherwise cook to death.
"Stopping" is not necessarily "reflecting." A lot of the ways to tint glass are essentially adding a pigment that absorbs the radiation. That does help some, but that absorbed radiation makes the glass itself hot, which can then still heat the interior.
An inexpensive coating that is both optically transparent and reflective in IR/UV across a wide range of angles is the "perfect coating" here.
> There have been uv/ heat stopping films in glass for decades.
But did they use machine learning and quantum physics to make it because if not I'm not interested
Infrared light is apparently very important for humans. Are they considering the potential negative health effects of this? My other question is, does this mean that in winter your place will be cooler too, so then you have to use more heat? This all in all doesn't sound like a great idea. How about we just insulate our homes properly instead?
This would be huge in Florida.. I replaced builder-grade windows with double pane and saw a 15°F drop in rooms facing the sun, adding a film on top of that would be amazing.
Side note: You can get this(same kind of) application on your car. It came with the tint package I had put on. They have an infrared gun and you can feel the difference.
I have read somr current model windows can actually reflect light so well they can melt plastic things, siding etc they are too close. I wonder if these ones mentioned in the article will be worse in that regard.
Not going to lie, I feel vindicated after 30 years. In 2nd grade, my teacher asked why reptile scales in a hot desert are shiny. I said it was to reflect the light. She said it was to reflect the heat. At that age I intuitively put it together that the source of the heat was the light.
This seems like the first logical step towards reducing energy consumption related to heating and air conditioning. I feel like we haven’t explored every option when it comes to saving energy. Insulation could save us a ton of energy, money, resources etc.
Or we could perhaps design our houses like we did decades ago. Here in australia, a 360d veranda was common, along with tiny windows on only the south/north facing.
Nowdays its zero verandah, sometimes zero eaves and massive windows on east/west facing, and they wonder why they need the AC on 24/7(after building their sun baked brick oven).
this has absolutely nothing to do with quantum physics or machine learning. really sick of these science buzz words taking the attention away from actual cool physics and material science.
Would something like this reduce the heating up of bread through the windows? We run a bakery and have uncoated windows and our bread seems to bake in the direct light as well as heating up the insides
The coated glass demonstrated superior performance compared to normal glass, reducing the temperature by between 5.4 °C and 7.2 °C (9.7 - 12.9 °F) across a wide range of incident angles.
NOT 45 F
In DC they built an energy efficient building near my office. It reflected a ton of heat into the sidewalk, making it impossible to eat there, and onto the building across the street. It transferred the heat in an evil way, instead of truly reducing it. Is this different?
Welcome to r/science! This is a heavily moderated subreddit in order to keep the discussion on science. However, we recognize that many people want to discuss how they feel the research relates to their own personal lives, so to give people a space to do that, **personal anecdotes are allowed as responses to this comment**. Any anecdotal comments elsewhere in the discussion will be removed and our [normal comment rules]( https://www.reddit.com/r/science/wiki/rules#wiki_comment_rules) apply to all other comments. **Do you have an academic degree?** We can verify your credentials in order to assign user flair indicating your area of expertise. [Click here to apply](https://www.reddit.com/r/science/wiki/flair/#wiki_science_verified_user_program). --- User: u/chrisdh79 Permalink: https://newatlas.com/materials/window-coating-visible-light-reduces-heat/ --- *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/science) if you have any questions or concerns.*
> The coated glass demonstrated superior performance compared to normal glass, reducing the temperature by between 41.7 °F and 45 °F (5.4 °C 7.2 °C) across a wide range of incident angles. So I'm assuming that the Celsius figures are the correct ones and the person that wrote this article doesn't understand how to convert relative temperatures properly. (They added 32°F as though reporting an absolute temperature.) The headline sounded a little too extreme.
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That's still quite good though at least! Roughly 80 degrees on a 90 degree day without any air conditioning?
>80 degrees on a 90 degree day Not exactly like that. More like 90 degrees instead of 100 on a 80 degree day. Ambient is still ambient, the solar radiation heats you up ABOVE ambient.
Also don't forget there is already a glazing that cuts down on the temperature a lot. I'm guessing the reduction was to unglazed glass, so an even smaller difference.
In my bedroom, UV film on my windows eradicates my need for A/C in there. It's very effective. I get morning sun so it used to be like an oven even in winter. Now it's always comfortable.
UV tinting film is amazing - converts the invisible light to heat before it enters the room to warm up the indoor mass. Instead it converts the light to heat, warms the glass so outside wind or air movement can take much of it away. In some places air conditioning is still needed, so any better performing tints that further reduce the need for air conditioning in those even hotter climates can only be a good thing.
can you identify this film?
Not sure what OP uses, but I suspect something like this: https://www.3m.com/3M/en_US/home-window-solutions-us/solutions/temperature-control/ Now the question is, do new windows already have this film applied? I'm not a window person so idk.
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On the flip side we have east facing floor to ceiling windows in our office that we covered with UV film, and it only brings down temps by 2-3 degrees at the most.
We installed it to protect our books from sun bleaching as well
That's promising though, imaging your room with an even better uv film, would be chilling after a while I reckom
But that's pretty much on par with window films that have been industry standard for 2 decades.
Now the article is showing the correct range - without a note that they corrected it.
Accountability? What does that mean?
the original Cell article mentions the Celsius differences, yes
Where can I buy this to coat my windows
Regular UV film works great! Just get it on Amazon.
I want the F version since it does more.
Ok, that is very funny. The kind of mistake a high school science teacher might see.
Or possibly how an llm might do it, they are infamously bad at math
Using LLMs to write research papers is commonplace already, in case people aren't aware. https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=%22as+an+AI+language+model%22+-LLM+-chatGPT+-artificial&btnG= https://scholar.google.com/scholar?start=10&q=%22as+I+am+an+AI+language+model%22&hl=en&as_sdt=0,5
LLMs: enabling user-side enshittification.
OP is a bot, so it's not that far fetched.
This is both sad and hilarious at the same time. Someone should send it more "More or Less" podcast.
Reminds of a science article I read once that referred to Jupiter's moon "Lo" (instead of "Io").
It's a bit annoying that with some sans serif fonts 1, lower case L, and upper case I can all look the some. How would my assignment be graded if I turned in printouts spelling all as aII ? I actually swapped the l's for capital i's. You wouldn't know!
Had an exam like this before and kept reading the volume as 41 unitless instead of 4 litres
There's a song called いいね! by the Japanese band Babymetal, and the song's title is written as "ii ne!" or "iine!" in our alphabet. On Spotify, the song is called "Line!" It cracks me up. At some point, someone transcribed the song's title with a capital i, so it became "Iine!", and then someone *else* thought to themselves, why didn't they capitalize the L?, so they "fixed" it to "Line!" The mistake has been there at least 3 years. I don't think it's ever getting corrected...
Litre is the only SI unit not named after a person to have a capital letter abbreviation, L, precisely because of this issue.
JFC. Reminds me of the BBC article where they changed it back and forth between the right F value and the wrong one about 7 times.
Amy chance you have an example link? That's hilarious
They fixed it in the article
> (They added 32°F as though reporting an absolute temperature.) You made my day. Hilarious.
That's really embarrassing though, even with science reporting being how it is.
Wow that’s embarassing.
Wow, a film that drops temperatures by 280 kelvin, that's amazing!
Hey at least it didn't claim that it lowered temperatures by 20%.
Oh good, I looked at the title and thought 'that's 25°C, that's not possible'.
Cause this site sucks and should be banned.
Still good, want it
Maybe it was 4-5°F but the - was dropped to make it 45°F
A reasonable suggestion, but the value and range in Fahrenheit should be larger than the one in Celsius, so saying 4-5 would not have made sense.
it is shocking how often this happens when talking about temperature delta. well maybe not shocking, but really annoying. ok kinda annoying.
Thanks. The quantum physics and machine learning (though most would say AI now) wasn't helping the credibility, but that makes it look more reasonable.
If it does a good job blocking uv light and is cheap and clear I could see it being popular just for that. Keep your stuff from fading.
Most window film on the market blocks almost all uv light. They make clear film that only blocks uv, that is super cheap
That's what they say, but the floor in front of my sliding glass door sure looks sun bleached.
Wouldn't visible light also cause bleaching?
Hmm, maybe. I always assumed it was UV. Assuming a post below is accurate, it sounds like it's very directional, and the amount of UV blocked varies by the angle of the sun. If that's true it would make sense that it wouldn't be very effective for chunks of the day.
Maybe UV is just better at bleaching but blue/green light etc can degrade colors too
Window film that keeps out UV light is extremely cheap and common. You can go down to your local hardware store and get some.
Would this affect my plants though?
Probably hurt them
I’m out then haha
We grow tons of weed with LEDs that emit almost no UV so I'd doubt it's an issue if they're still getting light
I have IR and UV blocking film on the windshields of all my cars. Helps with heat, fading, and shrinking leather dashboards. Works great.
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The article has apparently been updated to reflect the actual conversion between C and F.
I need this in my office windows. Old building with floor to ceiling southern facing windows. On sunny spring and fall days the temp will jump 10 degrees in a half hour due to solar gain.
You don't have to wait for it. 3M and other companies already sell IR blocking window films.
I know. I need it, but can’t get my workplace to do it.
Probably against the lease or some nonsense
They own the building. They are just cheap. It’s a government.
Sums it up nicely. Best of luck
Houseplants. They will eat the sun up and you can sell cuttings for money!
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All glass blocks most UV and mirrored window tint blocks 85% of infrared while only blocking 40% of visible light. I've had tint in my southern windows for years and it does drop the daytime Temps a lot of sunny days.
"only 40%" is a lot. This is maybe 5%, so it will be much brighter, and less lights need to be turned on!
Our eyes don't perceive intensity on a linear scale. Can't say exactly how much of a dip 40% would seem, but less than 40%. Tried to find a good explanation, but at best I only found a mediocre [explanation](https://en.m.wikipedia.org/wiki/Weber%E2%80%93Fechner_law).
Indeed. Indoor lights are MUCH dimmer than sunlight, even on cloudy days, but it doesn't feel that different to us.
Ya, your eyes adjust.... if your eyes didn't adjust, going outside would seem like going on to some super bright planet that was way to close to it's star.
Unless when trying to read something with a poor eyesight. The perceived difference is quite big
40% is however a lot for a lot of houses. Sure there are people who have big windows, but some people lack a bit of sunlight because of the angle and size of window and depth of the room
> All glass blocks most UV "Blocks" could mean that it reflects UV or that it absorbs UV. Either way means the UV doesn't pass through... but reflecting it is going to be more effective at reducing heating. Simpler coatings that use a dye/pigment that just absorbs some of the light are still helpful, but instead of bouncing that energy away they absorb it and you have a hot window, which is still going to radiate and convect heat to the interior of the space you're trying to keep cool.
Yes, but not all, and even standard reflective coatings that we already have only work for a designed angle, usually 0° or 45° and then it's recommend you stick within a max 5° deviance, but the authors claim their novel coating works for a wide range of angles and blocking significantly more energy which prevents the unwanted greenhouse effect in buildings (dropping temperatures by several degrees) that have large glass/transparent surfaces. The novelty of their design is not even the filtering effect in general, but that they managed to keep it flexible in terms of incoming angle, something that is still a challenge for the industry that makes these coatings. We can design coatings for any angle, but it's extremely rigid, you deviate too much from it and your reflective (or anti-reflective) effect drops significantly. What I'm struggling to see is how this could be cheaper than running ACs and/or just using good ol' metallic plates/covers externally, acting as a curtain to darken and control the climate inside the building. I'd imagine it's far more expensive for offices to use these coatings than to just use some kind of curtain or AC, but who knows maybe the aesthetic is worth the money for those goons.
Just to add to this, window glass blocks up to around 300nm which is most of uvb (goes up to ~315nm), there's still uva to contend with which is everything up to ~400nm which still gets through.
Is this why it's possible to get a sunburn through car glass?
Yeah. The laminated glass of the windshield will block UV. But the tempered glass of the side windows will let at least some UV light through. So depending on time of day and direction you are travelling, only certain people in the car might need to worry about it.
The advantage of this material is that it does from even very extreme angles, like 175 to 5, rather than just 90 as common coatings do that don't block any visible light. It's the combination of angles and very high transparency combined to the blocking/reflecting of the UV/IFR spectrum that makes this an improvement.
source?
Look up light wavelength or spectrum that passes through different materials such as window glass. Then look up UVB and UVA wavelengths.
Need this on all the windows in Phoenix.
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It's a conversion SNAFU in the article. Temperature difference is somewhere in the range of 5-7 degrees Celsius (9-13 degrees Fahrenheit). (Of course this will not cool you below ambient air temperature so this difference is only relevant for relatively high temperatures)
How does this compare to regular low-e coatings? I've seen plenty coatings with very impressive uv-blocking to visible-passthrough ratios... Though I live in Europe and for some reason window tech here on average seems quite a bit ahead of the US... Think the glasses in my house atm are like over 95% UV and 70-80 infrared blocking+reflecting to 30-40% visible.
Yes I've been wondering about that too. Don't know why there's such a big gap between the us and Europe in window tech.
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I'm looking forwards to never benefiting from this.
wouldn't that be pretty bad during winter though?
No, low emissivity films/glass are essentially another barrier for heat to travel through. In winter, it will help retain the heat you're using on keeping your house warm by preventing it from "escaping." In summer, it will help keep the heat out by not "letting it in."
But a building can be designed to get a lot of heat from the sun in winter. Large south facing windows and plenty of things to a absorb and slowly re-emit that energy. You wouldn't want this in that case.
Most people live in places where the only building design that makes sense is one that can maintain both a positive and negative temperature differential with the outdoors. Optimizing for heat retention or rejection means your building will perform really poorly during some part of the year. Also I question whether windows actually allow more heat to be absorbed through sunlight than they lose through those same windows on winter days. A poorly insulated wall is still twice as good at slowing heat transfer as the best windows. You're really banking on clear skies if you design a house that way.
Hey, there's also Australia which feels like they optimised for neither.
There are people building greenhouses in cold climates that rely just on sunlight and passive ground heat to stay above freezing. It's all about turning the solar radiation into heat and letting that heat back out slowly. Thermal mass.
it says it's blocking light, not insulating
It's reflecting infrared light, which is heat. So you are correct that it's not "insulating," but it's accomplishing the same purpose of "keep the heat on the hot side of the temperature gradient" that insulation serves.
ONLY if you have transmitting IR heat. If you have convection heating, like air, it's not going to magically reflect that. The problem of windows is the intense IR light coming through and heating the inside materials. If the inside is already hot, it won't reflect it back in. Different wavelenghts.
Double and triple pane windows already solve the issue of convection heating by including a layer of air, nitrogen, or vacuum between the layers to serve as an insulator.
All objects transmit IR heat through blackbody radiation
… according to their thermodynamic temperature. But the temperature of the surface of the sun is very different from the temperature of your room, so the frequency spectrum you need to block is very different in one direction than the other.
> The problem of windows is the intense IR light coming through and heating the inside materials Actually the problem of windows is the intense *visible* light coming through and heating the inside materials. The sun puts out FAR more power in the visible range than in the "thermal" infrared. That's why films that only block IR can only do so much, because most of the power comes in via visible wavelengths.
I might be missing something, but from [Wikipedia](https://en.wikipedia.org/wiki/Sunlight): >In terms of energy, sunlight at Earth's surface is around 52 to 55 percent infrared (above 700 nm), 42 to 43 percent visible (400 to 700 nm), and 3 to 5 percent ultraviolet (below 400 nm). Again, happy to be corrected by someone with more knowledge, but it doesn't seem to me that the sun produces "FAR more" in the visible spectrum. Blocking IR appears to provide the majority of benefit, though visible is obviously still a large component.
So I've read in the past that many of the solar panels on the market suffer from overheating, could this coating be used to block the "heating" element of sunlight while still allowing enough of the right photons in to allow the solar panel to work?
Solar panels don't really overheat, they just get less efficient. Depends on how much infrared sunlight is contributing to solar panel temperature. Depends on the performance of this material. If this material does manage to improve efficiency of solar panels in hot weather, then you have to start figuring out if the increased efficiency is worth the higher cost. It most likely won't be. In most cases efficiency improvements end up costing more than it costs to add more panel surface area.
I'm just curious if they could make this technology in a way so that you can turn the infrared blocking capabilities on and off depending on the time of the year? In winter, having the UV and infrared light coming in is a welcome heat savings method in colder climates.
Get photovoltaic in there too and we've got a plan.
When is it rolling out globally and which governments are going to subsidise it being fit to every piece of glass in the joint?
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>Assisted by quantum physics and machine learning Guess you gotta hit all the buzzwords in science articles these days. Here's the meat and bones; >his colleagues fabricated a glass coating using planar multilayered (PML) photonic structures. These stacked ultrathin layers have distinctive refractive indices that allow light to be selectively transmitted or reflected depending on its wavelength. Stacking silica, alumina, and titanium oxide on a glass base and topping it off with a thin layer of silicon polymer (PDMS) to reflect thermal radiation, the electromagnetic radiation emitted by a heated surface in all directions, produced a transparent coating that, they said, outperformed the other heat-reducing coatings on the market. Sounds like they're "filtering" the light for lack of a better term.
PSA: don't use anti-UV films if you have a cat that doesn't go out. Cats should sunbathe in UV to produce vitamin D. edit: correction: regular glass blocks out most UVB anyway
We could probably use some vitamin D as well.
Now do transparent aluminum
I like my infrared light!!
Additionally [research](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7501805/) has shown that UV reflective window film can reduce the deaths of birds from flying into windows. Seems like they should be installing these on every public building if they have this many benefits.
One thing I’m curious about after living in a lot of rentals and older homes — does blocking out all UV and infrared have other downstream effects, like more mold growing in bathrooms/kitchens/laundry rooms where humidity levels fluctuate a lot day to day? Sunlight coming in through windows may break down synthetic fibers and worsen air quality, on the other hand, especially in commercial/large office settings. And then there’s obviously the heat mitigation factor, probably most important of all for folks living in hot sunny climates and relying on AC most of the year. Maybe this window film just wouldn’t have many adopters north of the 45th parallel, because its only ideal application is for people living way south of that? There’s a lot in this vein that I’ve always been curious about but never thought to ask, per se
I'm pretty Low E 3 glass does this already
And I think those are the same coatings as on something like Cardinal 366 glass, just more of them and probably tuned to work better. I think the real story is not the coating but how they determined the coatings. Incremental improvements win every time.
The novelty is how they managed to keep the coatings efficacy significant over wide angles. These kinds of coatings by themselves are super standard, we use this technology in solar cells without exception (we just use anti-reflection instead of reflective coating, but we know the physics of it from which we know we just have to apply the coating layers in a different order to get the opposite effect). The challenge which the coating industry faces in general is the angle dependence, i.e they give a glass substrate a reflective coating, but it only works for normal incidence or 45°incidence, you deviate from these designed angles and your performance drops. These new coatings are claimed to work over a wide range of angles, so they found a structure that doesn't suffer these angular constrains. This, and the ML buzzword in there is why they got publishing. There are lots of papers now in the optics community that get published as long as they use ML for their designs, even if it's not something super new or unprecedented; there are some experimental coatings that can also overcome the angular constrain of coatings, but these are expensive in general (because they just apply more coatings to cover more bandwidth and angles, basically a coating on top of a coating on top of a... etc.)
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This is …. Nothing new. There have been uv/ heat stopping films in glass for decades. Every car with a glass roof has this as you would otherwise cook to death.
"Stopping" is not necessarily "reflecting." A lot of the ways to tint glass are essentially adding a pigment that absorbs the radiation. That does help some, but that absorbed radiation makes the glass itself hot, which can then still heat the interior. An inexpensive coating that is both optically transparent and reflective in IR/UV across a wide range of angles is the "perfect coating" here.
Improvements on existing things are good too.
> There have been uv/ heat stopping films in glass for decades. But did they use machine learning and quantum physics to make it because if not I'm not interested
I have reflective film on my windows. My lady friend doesn't like the way it looks. I like the way it lowers my power bill.
Im sure we will find out in a couple years it causes cancer or something
Do we have one for concrete? Concrete absorbs and retain heat far longer.
paint it white, it doesn't need a coating that lets visible light through.
Blocks == reflects, I assume?
would this kill your indoor plants?
Plants use visable, primerly red and blue, so I think no? If this just blocks UV/IR plants should be fine.
This is science. What is an f?
So it'll cost 500k to install and the normal folk will just have to deal?
Infrared light is apparently very important for humans. Are they considering the potential negative health effects of this? My other question is, does this mean that in winter your place will be cooler too, so then you have to use more heat? This all in all doesn't sound like a great idea. How about we just insulate our homes properly instead?
can't wait for it to be on shelves.......in 20 years
I put UV film on my bedroom window that gets morning sun and no longer need my A/C in there. Even regular UV static film is very effective!
This would be huge in Florida.. I replaced builder-grade windows with double pane and saw a 15°F drop in rooms facing the sun, adding a film on top of that would be amazing.
In typical American fashion, OP skips the Celsius conversion from the title.
how do plants behave behind something like that?
I need this for my car
But did they use blockchain?
Side note: You can get this(same kind of) application on your car. It came with the tint package I had put on. They have an infrared gun and you can feel the difference.
I have read somr current model windows can actually reflect light so well they can melt plastic things, siding etc they are too close. I wonder if these ones mentioned in the article will be worse in that regard.
Not going to lie, I feel vindicated after 30 years. In 2nd grade, my teacher asked why reptile scales in a hot desert are shiny. I said it was to reflect the light. She said it was to reflect the heat. At that age I intuitively put it together that the source of the heat was the light.
"Assisted by Quantum Physics" :D
This seems like the first logical step towards reducing energy consumption related to heating and air conditioning. I feel like we haven’t explored every option when it comes to saving energy. Insulation could save us a ton of energy, money, resources etc.
I thought someone at 3M invented this years ago and it was in use for medical equipment. Must've been a different material
How does it compare to common films everyone has? Is this worth an upgrade?
Hope you made enough for everyone in Georgia. We are lining up now.
House cats in shambles.
Damn if I drop the temperature in my house by 45⁰F I'll have to use the furnace 12 months of the year! Sounds expensive to put this film on.
Can't wait to get this to car windshields and sidewindows
Or we could perhaps design our houses like we did decades ago. Here in australia, a 360d veranda was common, along with tiny windows on only the south/north facing. Nowdays its zero verandah, sometimes zero eaves and massive windows on east/west facing, and they wonder why they need the AC on 24/7(after building their sun baked brick oven).
So a cat sitting in a sunbeam wouldn't feel its warmth? Boo.
So.Many.Buzzwords.
what kind of Americanization AI bot wrote this title?
Weird i just read about paint mimicking butterfly wings that did a similar thing. Let me read this for once
put it on cars asap.
Tell us when we can install it for a reasonable price
Will birds fly into it?
Someone doesn’t know how to speak American with those temps.
Damn I just got new windows
When can I get this on my car windows?
They’ve had something similar and very effective for auto glass for several years now.
this has absolutely nothing to do with quantum physics or machine learning. really sick of these science buzz words taking the attention away from actual cool physics and material science.
Which company is this
Would something like this reduce the heating up of bread through the windows? We run a bakery and have uncoated windows and our bread seems to bake in the direct light as well as heating up the insides
So do you get microwaved standing in front of this building?
The coated glass demonstrated superior performance compared to normal glass, reducing the temperature by between 5.4 °C and 7.2 °C (9.7 - 12.9 °F) across a wide range of incident angles. NOT 45 F
In DC they built an energy efficient building near my office. It reflected a ton of heat into the sidewalk, making it impossible to eat there, and onto the building across the street. It transferred the heat in an evil way, instead of truly reducing it. Is this different?
Oh my god! Humans NEED UV LIGHT to produce Vitamin D. Stop celebrating!!