Whoever looked at a wall thousands  of years ago and added the first   hole to let some light in sure was onto something.

Windows are amazing, even if I personally  cannot live without my blackout curtains. And window technology has made some  major advances over the millennia.

Like adding screens to keep bugs out,  or double glazing to keep heat in. But I think it’s pretty clear:  scientists have yet to perfect windows. The main challenge these days is to  create something super energy efficient… something that doesn’t force us  to use a bunch of electricity to   keep a building’s insides the Ideal Temperature.

But boy are scientists  creating some nifty solutions. Here are five futuristic windows that  may be coming to a wall near you. [♪ INTRO] If you let sunlight in through  a window, you also let heat in. Sometimes that’s great, like when you’ve built a  greenhouse or it’s winter in the American Midwest.

And sometimes, that’s the opposite of great…  like when it’s summer in the American Midwest. One technique you can use to block some  of the heat is to put a film on the glass. It keeps heat out, and uses a lot  less energy to keep rooms cool,   making buildings much more energy-efficient.

But while we’ve been slapping films  on windows since at least the 1960s,   there’s one problem in the R&D of  it all that keeps sticking around: In laboratories, a lot of films are  optimized for a 90 degree angle of incidence. That means they’ll block the most light and heat   when light comes at them perfectly  perpendicular to the window pane. The Sun, you may have noticed, is rarely  beaming light into a building at that angle.

For most of the day…especially when  it’s the hottest part of the day…   all that light is hitting your typical  vertical window at a very sharp angle. If you’ve optimized your film for  light to hit at 90 degrees, it’s   gonna be performing near its worst  right when you need it the most. So a paper published in 2024 goes into  how one team went ahead and designed a   film that works great at a whole bunch of angles.

In other words, as the Sun’s position  changes over the course of a day. It requires a series of different layers,   placed in a specific order determined by  some quantum computer-assisted modeling. Each layer has a unique refractive index,   meaning it bends the light that enters  or exits it by a certain amount.

So, by stacking those layers on top of each  other, the scientists were able to fine-tune   just how the light bounced and keep out as  much heat over as many Sun angles as possible. When the team tested their film  on vertical windows outside,   it reduced temperatures on the other side  of the glass by up to 5.4 degrees Celsius. Although I should note that’s compared  to a naked pane of “normal” glass,   not one covered in a standard, commercial film.

As for when you want to keep  the air inside nice and toasty,   well, let’s turn to our next innovation: Vacuum seals. No, I don’t mean a cavalry of cute  marine mammals riding roombas. But I like where your creativity took you.

If you want to transfer some heat,  you can do so one of three ways: Conduction, basically direct contact; convection,   basically the mass movement of a fluid like  water or air, like how your oven works; and radiation, basically traveling through space   as energy waves and warming  things when they absorb them. So if you want a window to  avoid transferring heat,   you could try preventing at least one, if  not more, of these methods from working. For example, the company LuxWall has created  what they call Transparent Insulation.

The basic structure comprises two planes  of tempered glass with sand grain-sized   “structural micro-pillars” that  keep the panes from touching. They’re similar to dual-pane windows  in that they use two glass panes,   but instead of air or some other gas  sandwiched between them, there’s nothing. It’s a vacuum.

Or as near a vacuum you’re able to get. Each window has a little evacuation port  in the corner, to suck all the air out. And to capture any stray molecules  left bouncing around between the panes, and create an even stronger vacuum,   these windows also feature what  engineers call a “Thin Film Getter”.

Yes, that’s a real term you  can read in academic papers. I know it’s terrible. With practically no molecules  between the panes…remember gases   are technically fluids…there’s  no opportunity for convection.

And with nothing between the glass panes  besides those structural micro-pillars,   there’s basically no chance of conduction. That leaves just radiation as a  viable method of heat transfer,   and Luxwall has added a low-emission  coating to block a lot of that, too. Now technically, the idea to use vacuum  insulation in windows is far from new.

A German patent titled “hollow  glass pane”...except, you know,   in German…dates all the way back to 1913. And commercial products have  been around since the 90s. But until recently, there  were limited applications.

The windows were too expensive and didn’t hold   their vacuum long enough for it  to be worth it for most buyers. Thanks to innovations across the fields  of physics, ceramics, material science,   and manufacturing automation,  that’s starting to change. But maybe, the future of windows doesn’t involve  glass at all, vacuum insulated or otherwise… Because scientists are also on the hunt for  new materials to make their windows out of.

And one team has decided to work with…wood. Not in a board-up-your-windows way, either. This is fancy, see-through wood.

Why wood? Well, one reason goes back to  the don’t-let-heat-in thing. Wood is about 25 times better  at trapping heat than glass,   so some scientists have been  experimenting with ways to   make it clear enough to peer through in the  hopes of finding a cool window alternative.

Wood, at a basic level, is made up of three main  molecules: cellulose, hemicelulose, and lignin. There’s also water and some impurities,  but that’s the most important stuff. And if you do the right chemical reactions  to remove or de-pigment the lignin,   you can get a relatively transparent result.

Especially if you fill it with  something like clear epoxy. However, epoxy comes with its own  problems, like not being biodegradable. So, in a paper published in 2025, one team from   Kennesaw State University in Georgia set  out to make an eco-friendly alternative.

Inspired by the use of egg whites as building  materials in ancient India, the team used sodium   sulphite to strip balsa wood down to what’s  basically a lignin-free cellulose skeleton. Then, they filled the holes in that skeleton  with a mix of rice extract and egg whites. Voilà.

A sort-of-clear window. I know, being only semi-transparent  and brownish isn’t ideal. But it’s a start!

Meanwhile, if you’re not a fan of  balsa wood, you could try bamboo. Which I know isn’t wood; it’s grass. But it feels similar, and it’s made of  most of the same basic chemical compounds.

So it’s worth a mention. And turning it into windows is a very  similar process: Remove lignin from plant. Make remaining structure strong  enough to stand on its own.

The researchers behind this experiment soaked  bamboo in an acid until all the lignin was gone. But to make it strong, they  didn’t fill the gaps in. They just smushed the bamboo down until it  became a thin, flexible, whitish material.

So our bamboo window also isn’t clear. But hey, at least frosted  glass windows are a thing! Plant-based windows may not let all  the light in that you might want.

But with more sophisticated materials,   researchers are also inventing window panes  that can change how much light gets let in. In 2025, a team from the Korea  Advanced Institute of Science   and Technology published their  research on electrochromic tints. They’re made of molecules that change  color when subjected to electricity.

To support the flow of that electricity,  the windows have three main components:   an outer layer of glass, an inner layer featuring an electrochromic  chemical called Prussian white, and in the middle, an electrochromic  gel filled with dissolved silver. Each window pane also has 3 modes. Mode number one is “clear”.

It just lets all the light  through like a regular window. Mode number two is what the  researchers call “colored”. By sending electricity through the setup,   a chemical reaction turns the  Prussian white into Prussian blue.

The new blue color blocks a bunch of both  visible and infrared light, but not all of it. So everything inside is a bit less  illuminated, but it stays colder. Finally, there’s mode number three: reflecto-mode.

When a more powerful electric signal gets applied,  the silver basically un-dissolves out of the gel   and turns into a mirror, reflecting pretty much  all light and heat to keep the room extra cool. And the best part? All of these changes are reversible.

Turn off the electricity, and  you go right back to clear. Meanwhile, another team has used a  mix of plain old water and tungsten   oxide to create their own 3-mode dynamic window. Tungsten oxide is also an electrochromic  material, like the previous team’s Prussian white.

But by itself, it only has  two modes: clear and dark. To get an in-between, the team added some  water to create tungsten oxide hydrate. The resulting hydrate did not  become a perfectly tunable window…   you can’t tune it like a light on a dimmer… but with the right amount of electricity, it could  let visible light through while blocking infrared.

It may not make your living room as  cold as the dark depths of the sea,   but hey, you can only ask so  much from a few water molecules. And that’s not even the liquid-iest  that cutting-edge windows get! In 2023, researchers at the University  of Toronto created a prototype full of   channels through which they could pump different  liquids to give their window different properties.

The whole system was inspired by  the color-changing skin of squids. In one experiment, they made a tiny “room”  with their prototype window on one side,   lit that room from the outside  with a 100 watt lightbulb,   and measured the internal  temperature of the test room. Once it got up to 39 degrees  Celsius, the team used a syringe   to add a specially prepared fluid that  included little particles of carbon.

Those particles would float around and block some  of the light from the bulb, cooling down the room. In fact, the room got down to  32 degrees in just 15 minutes,   without the carbon blocking much visible light! In theory, you could stack layers  of these liquid-filled window panes   together to block out even  more light at a given time.

Like Layer 1 with Fluid 1 blocks infrared light,   Layer 2 with Fluid 2 blocks  some visible light, and so on. Even more in theory, the researchers eventually  want to replace the currently manual controls   with a fancy computer program that would learn  what a specific window’s needs are over time, and   then adjust itself throughout the day to let the  ideal amounts of right wavelengths of light in. All, of course, to keep those energy bills low.

But personally, I think their stretch goal  should be to make windows shaped like squids. There has to be some kind of seafood  restaurant that would buy them,   or an independently wealthy teuthologist. Did you know that’s what they  call people who study squids?

Because I sure didn’t. As helpful as they’ve been to human civilizations,  windows could still use an update or two. Maybe five… And thankfully, scientists are on top of it.

Some innovations are ready for purchase,  and can continue to be improved. Some are still solidly in the R&D phase. Personally, my favorite is the  squashed down bamboo frosted windows.

But let me know when they make a window  that can replace my blackout curtains. Support for this episode was  provided by Breakthrough Energy. [♪ OUTRO]