Do things painting the roof white help to reduce the heat in a significant way? Have seen it being mentioned in videos on black vs white coloured cars.

Are there any drawbacks noted by people who tried it for roofs?
Or are there other options that are easier to start with?

Yes, very effective. I worked in commercial construction for a few years.

We didn't use paint, but the gist is the same. A black EPDM roof may reflect about 5% of incident irradiance and a white TPO roof reflects about 80% which means that a white TPO roof reflects 16x more light than a black EPDM roof and the black roof absorbs 4.75x more than the white.

This means white is easier to cool in the summer and black is may be easier to heat in the winter, but the amount of sun in the winter is less so its not like 1:1.

I live in south Florida and replaced/resurfaced the asphalt parts of my roof with white PTO and silicone elastomer. It lowered power usage from AC by about 10% in the main zone and much more in a smaller zone where the AC ran constantly because it couldn’t maintain the temp (77F) with the black roof. That seems to be in line with current research but YMMV.

https://www.youtube.com/watch?v=36D6CzghGfw

One of the drawbacks he found were moisture problems inside because of the cooler temperatures, but this was in his shed. Though he's testing more than just white paint, he's testing daytime passive radiative paint.

That’s a wild drop, I didn’t realize it would be that impactful!

Yep, tho it’s probably mostly because my house is old and poorly insulated.

Yeah it works. The drawback is you gotta do it.

If you’re only fighting heat and have a tall area then transom windows can also help a ton but you have to have a massive gigabrain from 1950 to understand how to use em.

Thank you.
Transom windows are the type that are above doors?

I forget what tropical place my parents went, but all the roofs were white for that reason

Above doors or above other windows. They’re the ones up high that pivot open and closed.

All true, great post. I can only add that proper attic insulation matters much more for indoor warmth in winter than the color of the roof itself.

Painting a roof white has shown a measurable lowering of temperature inside the building. Any issues are likely caused by the material used to make the roof white.

That's what he is testing in that vid, but you should also mention that he tested the stupidly expensive radiative paint against some paint that he just whipped up himself, and his paint vastly outperforms the special paint he bought.