This article talks a lot about “cool roof” but doesn’t actually tell what it is. A "cool roof" is a roofing system designed to reflect more sunlight and absorb

This article talks a lot about “cool roof” but doesn’t actually tell what it is. A "cool roof" is a roofing system designed to reflect more sunlight and absorb less heat than a standard roof. Cool roofs are typically made of materials or coatings that have high solar reflectance (the ability to reflect visible, infrared, and ultraviolet wavelengths of sunlight) and high thermal emittance (the ability to radiate absorbed or non-reflected solar energy). It makes me wonder what is a good roof design for more northern areas - i.e. in Seattle you want “cool roof” in the summer and “hot roof” in the winter.