What are Cool Roofs?
Cool Roofs use spray down liquid elastomeric materials that are highly reflective of the sun’s radiant heat. They are energy star rated keep the surface and structure cooler, as a result.
One issue given enormous attention in the last few years is the usage of Cool Roofs to mitigate the Urban Heat Island effect. The Urban Heat Island effect is the creation of higher ambient temperatures in densely compacted urban areas than the surrounding suburban areas. It is a result from reduced vegetative growth as well as a higher incidence rate of black or dark colored pavement and roofing. Typically, Cool Roofs are those with a solar reflectivity value of 0.75 or higher when new. That means 75% of the total radiant heat energy is reflected back into the atmosphere.
As much as 40% of a city’s impervious area is composed of roof area.
What is an Urban Heat Island?
When a large percentage of your city is covered by black roofs more cooling energy is needed for occupied spaces in these urban areas. There is also a higher rate of air pollution created to cool the inside envelope of buildings effected by the heat island effect. In the northern half of the country in areas like Michigan, Ohio, and Indiana, weather can change at a rapid pace. This sudden rise or drop brings a large amount of thermal shock to roofs that are black. Having a white roof reduces thermal shock.
Cool Roof Studies:
Studies have shown that if cities were to install only Cool Roofs, significant energy savings would result as well as an improvement in urban air quality. These studies have led to local and state-mandated commercial roof regulations. They are rapidly proliferating to other locales that see cool roofing as an inexpensive means to reduce overall energy consumption. Such programs as Title 24 in California and regulations in the State of Georgia, Salt Lake City, Chicago and other urban northeastern cities are examples of trends being adopted nationwide.