Revolutionary Paint: How to Make Surfaces Stay Cool in the Sun
Why Hacker News recommends it
HN points to it as an impressive, hands-on DIY demonstration of passive radiative cooling that works in practice.
What it is
Tech Ingredients shows how to make a homemade radiative cooling paint, with a custom liquid panel that cools below ambient temperature outdoors. The video covers the materials and how to apply the paint.
Recommended by 5 HN commenters across 5 different months, 2023 to 2026.
What Hacker News said
Recommends slimsag · 2023-04 · on “Energy-saving coating without pigment keeps the surface beneath cool”
Two YouTube researchers[0][1] (they make science content that is very much not in the traditional form of YouTube) have been working on Infrared Cooling Paint for almost a year now and have been detailing how individuals can make it at home (although a fairly involved/lengthy process today.) There's definitely something here, hopefully someone sells it pre-made, I'd love to try some. [0] [LINK] [1] [this video]
Recommends bertil · 2023-05 · on “Vietnam records highest ever temperature of 44.1C”
Technology Connection is a fantastic YouTube channel that shows how to build all sorts of useful things. Their latest video is on passive cooling and very impressive. [this video] Warning: the “senior-engineer; knows how to make stuff” energy from that channel is off the charts. Enough to warn people on HN.
Recommends Azrael3000 · 2023-07 · on “Making Radiative Sky Cooling Paint (With Novel CaCO₃ Microsphere Synthesis) [video]”
You can check out Tech Ingredients video [0] on the same topic, which will give an answer to your question. It is: Yes, it is better than regular white paint [0] [this video]
Recommends scotty79 · 2023-11 · on “Passive radiative cooling ceramic with high solar reflectivity”
Great video about making home-made high reflectivity paint: [this video] Aluminium plate painted with this paint is cooler when exposed to the sun not only than unpainted plate but also ambient air which feels really magical for me.
Recommends slimsag · 2024-03 · on “Using a solar oven as a radiant refrigerator at night”
You might like NightHawkInLight's videos on the topic[0] and Tech Ingredients[1] - they've been working on making paint using this technology with an at-home DIY process and experimenting with it. [0] [LINK] [1] [this video]
Recommends 20after4 · 2024-03 · on “Using a solar oven as a radiant refrigerator at night”
Sort of related: the YouTube channel "Tech Ingredients" do some cool things with radiant cooling: [this video]
Cites energ8 · 2025-06 · on “NASA's Voyager Found a 30k-50k Kelvin "Wall" at the Edge of Solar System”
It's a thing in from thousands of years ago [LINK] and today [LINK] for PDRC there are a couple good videos about it from NightHawkInLight [LINK] , [LINK] and Tech Ingredients [LINK] [this video]
Cites Llamamoe · 2025-10 · on “The World's 2.75B Buildings”
Are you perhaps thinking of radiative cooling, e.g. paint that reflects close to 100% of all light, excluding the spectrum at which room-temperature objects radiate heat, resulting in a net cooling effect? E.g. [Revolutionary Paint: How to Make Surfaces Stay Cool in the Sun]( [this video] )