I think with a material like this you would use both. Based on the article, it sounds like this material has a fixed cooling effect for a given temperature and

I think with a material like this you would use both. Based on the article, it sounds like this material has a fixed cooling effect for a given temperature and incident radiation flux. So if you want to maintain 75F in a building and outside it's 110F -- this material would reduce the cooling effort to the same as a normally insulated building where it's only 100F outside. A substantial energy savings. (I made up the 10F cooling effect, pick your favorite constant)