It assumes a 20-year life for white and black roofs and 40 years for green roofs. The white roof won, saving more than $40,000 in electric bills over the green roof. "White roofs win based on the purely economic factors weincluded, and black roofs should be phased out," he says. But, Berkeley Labs also points to the benefits of green roofs that could make them more attractive than white roofs, even though they cost much more. If the goal is to reduce storm water runoff and improve air quality, white roofs just don’t stack up, Chris Brunner, co-founder of New York Green Roofs, told Scientific American.