Interesting coating material, one more option for roof coating.
Materials like their "ultra-resilient" paintwork with Chromacool technology reduce the surface temperature of the vehicle by 20°C (68°F) and that of the interior by up to 4°C (39°F).
https://expeditionportal.com/hymers-vision-venture-sprinter/ (https://expeditionportal.com/hymers-vision-venture-sprinter/)
BASF markets the stuff; apparently, a pigment added to the paint. Bet it's expensive, auto paint products are already premium priced, this is just doubles the "premium", i.e. $$$$
http://www.dispersions-pigments.basf.com/portal/load/fid560473/Cool%20down%20your%20paints%20-%20Xfast_%20stir-in%20pigments%20forsolar%20heat%20management.pdf (http://www.dispersions-pigments.basf.com/portal/load/fid560473/Cool%20down%20your%20paints%20-%20Xfast_%20stir-in%20pigments%20forsolar%20heat%20management.pdf)
Windtrader, while a temperature of 4 degrees C is equal to about 39 degrees F, one degree C equals only about 1.8 degrees F. Hence, if it reduces interior temp by 4 degrees C, that would equal a reduction of 7.2 degrees F. That is substantial enough. A 39 degree F reduction would imply you could throw away your AC.
Good catch, that quote came directly from that article. Probably to research directly from the horse's mouth. https://aerospace.basf.com/heat-reflective-cool-pigments.html