These trendy roofs bring a new literal meaning to the word “cool,” as a recent study from the Energy and Buildings Journal suggests that white roofs are up to three times more effective than green roofs at fighting climate change. Traditional black roofs absorb heat and lead to the overall increase of the city’s temperature, known as the urban heat island effect. Recently, green roofs have begun replacing these black roofs to provide environmental benefits such as increased insulation, reduced stormwater runoff and reduced energy bills by decreasing the amount of heat absorbed by the building. However, roofs painted white receive similar benefits for a fraction of the premium installation costs of green roofs, saving up to 20% energy in hot and sunny areas by reflecting sunlight back into the atmosphere rather than being absorbed by the roof.
One of the biggest benefits of white roofs? They can be achieved from something as simple as a single white coating over the existing roof- no special engineering required.
So are white roofs the new sustainable replacement instead of green roofs? Not quite. While greatly lessening the effects of climate change and producing significant savings from reduced energy and installation costs, white roofs do not provide any advantage in stormwater runoff or urban aesthetics, in which green roofs excel. So the real answer lies in the concordant installation of both white and green roofs together, as their culminated individual benefits can help cities become as sustainable as possible!
Learn more about the study here: