person painting a roof on a sunny day person painting a roof on a sunny day A special paint could make houses cooler without electricity. (Photo: Chanchai Boonma / Shutterstock)

How the sun could be your new air conditioner

Scientists are using the sun to cool down houses covered with this special paint.

The idea that the sun could make your house cooler sounds absurd. But Israeli company SolCold has come up with a weird kind of paint that changes up the whole "sun making stuff hotter" thing.

The paint uses the energy from sunlight to cool down your house. It's called "laser cooling," which is when scientists point lasers at molecules to make them colder, kind of like how Albert Einstein's refrigerator used the sun to keep food cold.

"Lasers don't cool things," you might argue. "They're lasers. They burn things up."

It's pretty weird, but there actually is a way to use laser light and sunlight to cool things down. If you've got the right light (the sun) and the right substance (this weird paint), then pointing the light at the paint will actually slow down the molecules in the paint, making it give off heat. It's kind of like if you pointed a fire hose at a bear that was charging at you – the energy from the hose water would slow the bear down. Hopefully.

If you want to know more, check out this video of two people trying to be adorably quirky while explaining how laser cooling works.

People have long used white paint to scatter sunlight, but this stuff is on a whole new level. It doesn't just scatter light – it absorbs it and uses it to actually make a house colder.

“Heat from a building could be absorbed and re-emitted as light,” explained Yaron Shenhav, the founder and CEO of SolCold and a Tel Aviv University graduate.

When you paint a building with this SolCold paint, the top floor will be 10°C cooler. This could save a lot of money in air conditioning costs, which could in turn help the planet. Perhaps that's why the White House invited the company to join the Global Entrepreneurship Summit last year at Stanford University.

“It’s like putting a layer of ice on your rooftop which is thicker when there is more sun,” explained Shenhav. “As long as the sun is shining on it, it would be continuously cooled.”


Photos and SlideshowsPhotos and Slideshows

Related Topics: Science

How the sun could be your new air conditioner
Learn how scientists are using the sun to cool down houses covered with this special paint, all without electricity.