What is an ‘urban heat island,’ exactly?

white roofingOn this site, you’ll regularly see mentions of the “urban heat island effect” and our efforts to reduce it. But you may be wondering exactly what that term means.

According to the Environmental Protection Agency, these islands are created as the result of changes in the landscape in cities. With the addition of buildings and roads — and the subtraction of open landscapes and vegetation — the ground becomes less permeable and more dry. This causes the area to become warmer than their rural counterparts. Therefore, an “island” of heat is created.

How significant is the difference? On a warm summer day, the sun can heat exposed surfaces such as pavement to temperatures as much as 90 degrees hotter than how it feels in the air. These islands, on certain days, can be about 5 degrees warmer than the more rural areas. The effect is not fully diminished at nighttime, but it’s obviously more pronounced during the day.

Not only does this cause more discomfort (and possible health problems) for residents, but it also leads to other issues as well. Chief among them would be an increase in energy consumption. The urban heat island also causes elevated levels of air pollutants and greenhouse gases.

The EPA recommends several ways to combat the urban heat island effect. Among them: “Installing cool — mainly reflective — roofs.”

At GreenStar Roof Coatings, we have a goal of coating 10 million square feet of rooftops with cool roofs, thereby lessening the urban heat island effect in New Orleans. Contact us to get started on yours!