The Solution to the White Roof Weakness

"The upshot is that when the sun is shining a roof tile covered in the material is white-colored, scattering up to 80% of the sunlight back and thus keeping the building beneath the roof cooler. The result is a 20% reduction in cost to keep the interior at a comfortable temperature in the summer, a figure which also comes with an eco-friendly drop in the electricity supply demands. During winter, of course, you'd prefer your roof to capture as much heat as possible from the sun, which is where the black coloring is handy--the tiles scatter just 30% of incoming solar radiation then."