A comparsion of dark and white surface temperatures over the New York summer of 2011 shows a marked reduction in surface temperature (Image: Stuart Gaffin/Columbia University)
The white acrylic paint surface next to a black asphaltic control membrane on a Long Island rooftop (Image: Stuart Gaffin/Columbia University)
A comparsion shot showing albedo-loss of the acrylic painted surface over one year, before being relocated (Image: Stuart Gaffin/Columbia University)
Research by scientists from Columbia University and NASA suggests that painting rooftops white can result in temperature drop of over 40 degrees Fahrenheit during summer months (Photo: Erik Drost)
It's long been suggested that white rooftops could help reduce the heat bubble microclimates that surround our cities simply by reflecting solar radiation directly back into space, and in 2010 we reported on NCAR efforts to demonstrate the effect through computer modeling. A new study goes one better, putting the theory into practice and pitting three white materials against one another on three New York rooftops. The results of the study appear to be overwhelmingly positive, with white roof coatings reducing peak rooftop temperatures in summer "by an average of 43 degrees Fahrenheit (about 24 degrees C)."
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