Cool roofing is a roof that reflects sunlight and heat away from the building on which it is installed. The roof itself stays cooler and keeps the heat from radiating into the structure. Air conditioning equipment does not have to work as hard, and has the potential to significantly impact your electric bills.
Think of how a white t-shirt keeps you cooler in summer, while a dark shirt will absorb heat and keep you hotter.
Not all cool roofs are white or light colors. While a white roof reflects both visible and near infrared light, they are a more popular product, but there are membranes with darker pigment that are designed to reflect only the non-visible portion as well. Keep in mind that a white roof membrane will remain cooler than a pigmented roof and result in more reflection.
Saving money on your electric bill with cool roofing will depend on a few factors. Small roofs on tall buildings have less of an effect on energy savings than a large roof on a one story building. The more roof you have protecting your building, the more effective a cool roof can be.
Thermal shock occurs as the sun heats the roofing membrane during the day, and the rapid cooling in the evening. This causes your roof to expand and contract and will reduce the life of the roof itself. Thermal shock is greatly reduced with a cool roof membrane by reducing the expansion and contraction that happens daily.