During summer heat air conditioners are used extensively and this can increased energy consumption can be crippling. Black outs occur in the summer thanks to people cooling their homes and workplaces – but these power issues can be avoided. By simply painting roofs white it can help cool buildings and lower energy bills. Painting multiple roofs white can a really positive effect on a large area.
They found that urban expansion alone could increase summer temperatures by up to 6°F in some areas in addition to greenhouse gas-induced warming by 2100. The Mid-Atlantic and Midwest seeing the biggest overall summer temperature increases.
In all areas, white roofs could completely offset the combined increase in temperatures, and if deployed across the entire megapolitan area, could actually reduce summer temperatures compared to the 1990-2010 average.
The benefits of cool roofs were particularly prominent for the urban areas stretching from Washington, D.C. to New York, Chicago and Detroit, and California’s Central Valley.
Cooler summertime temperatures could reduce demand for air conditioning, which could both save money and reduce the chances of electricity grid blackouts.
Read more at Bloomberg.
A computer simulation of the urban environment has proven that in theory white paint on rooftops can significantly cool cities – thus saving energy in the summer that would be used for air conditioning.
Cities are particularly vulnerable to climate change because they are warmer than outlying rural areas. Asphalt roads, tar roofs, and other artificial surfaces absorb heat from the Sun, creating an urban heat island effect that can raise temperatures on average by 2-5 degrees Fahrenheit (about 1-3 degrees Celsius) or more compared to rural areas. White roofs would reflect some of that heat back into space and cool temperatures, much as wearing a white shirt on a sunny day can be cooler than wearing a dark shirt.
The study team used a newly developed computer model to simulate the amount of solar radiation that is absorbed or reflected by urban surfaces. The model simulations, which provide scientists with an idealized view of different types of cities around the world, indicate that, if every roof were entirely painted white, the urban heat island effect could be reduced by 33 percent. This would cool the world’s cities by an average of about 0.7 degrees F, with the cooling influence particularly pronounced during the day, especially in summer.
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