A white roof is coated with heat-reflective white coating which reflects up to 90% of sunlight. White roofs are much more than just white paint it is an indicator of the ability of a surface to reflect solar heat.
Heat Reflective Paint. It improves the insulation properties of buildings in an environmentally friendly manner. Generally, these paints are available in light colors because they can reflect up to 80% of the solar radiation.
Specialist heat reflective paints are also available, but their effect is minimal compared to going from dark to light colour. This coating allows more energy from the sunlight to bounce off than usual paint of the same colour. However compared to painting a dark roof with non-heat reflective light colored paint, the effect is only mild.
It is designed to reflect more sunlight and absorb less heat than a standard roof. The usage increases roof temperature and decreases room temperature correspondingly.