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] https://www.youtube.com/watch?v=dNs_kNilSjk

Unfortunately that video is real science presented like quack science... which is in a way the worst of both worlds!

Aahh the appeal to be contrarian at all costs just to look smarter.

Thanks for the link.

In my personal experience (and in the FLIR application guides) the main factor affecting paint emissivity is the glossiness (matte paint is much more emissive). I would have liked to see that test done with matte white paint, or at least have them mention that factor. From the video it was hard to tell, he said super bright Rustoleum, which isn't the same as matte. I would imagine emissivity to be more important that reflectivity given the result with aluminum (super reflective but still got super hot due to the extremely low emissivity).

I like the use of the thermocouples, but unfortunately it didn't go quite far enough...

The fact that he measures the back of the plywood controls for quite a bit I think. At 3m27s into the vid you see the plywood that has the 'paint' on the _other_ side is even cooler than the square that had been in the shade all along.

The insulator is just to prevent the plywood side that is measured to be heated by the ambient temp.