The introduction of single-ply roofing material also brought the opportunity to use roofing material in colors other than black. The advantages of a light-colored roof over a dark roof, as lobbied by environmentalists and some manufacturers, is high roof reflectivity. Roof reflectivity is the ability of a material to reflect solar energy, which can reduce cooling costs and energy usage.
That sounds like a win-win situation, but based on recent studies by the MRCA (Midwest Roofing Contractors Association), the reflectivity ratings (and energy savings) can vary drastically based on various factors.
To read more about the reality of roof reflectivity, below is an article published by the MRCA.
The Real Dirt on Reflective Rooftops