On the hottest of days, a black roof can hit temperatures as high as 185 degrees. We sought to prove this! Several Temperature monitors were placed on the New School University Building (66w 12th street) one month before converting it to white at the end of June. The roof was originally gray and it still reached temperatures of 155°F!
After the roofing was changed to white, the monitors were placed back and we saw a 50°F decrease.
The same experiment was conducted for Bowery Mission Building (227 Bowery).
Here are some great scientific articles on white roofs, green roofs, urbanization, and general environmental investigations that we at White Tops have found useful in our research and wish to share with our fellow earth advocates.
[click on the blue titles to view / download articles]
Passive Cooling Benefits and Properties of Reflective Roofs. Lee, Priscilla
This is a preliminary term paper I wrote in college and it's a great read if you want more depth on the problem and solution we have briefly addressed on our website. It further defines radiation, albedo, urban heat island, and peak energy demands. Including introductions to experiments conducted around the nation on effects of reflective roofing.
This experiment is one of our favorites. At only 14 years old, Ryan Wham helps clearly present why white paint is the most effective at cooling by using doghouses. His results simply expresses to the public a few dense concepts about material reflectivity and emissivity, pronouncing him worthy of the 2008 Scholastic science fair, Young Nationalist award, and press coverage.
Ryan tested the temperature difference between roofs with asphalt shingles, asphalt shingles painted white, tin, and tin painted white. Ryan uses this simple experiment to prove the hypothesis that a roof with reflective white paint has lower surrounding air temperatures than a dark roof.
Reducing Urban Heat Islands: Compendium of Strategies. Cool Roofs. Wong, E., Hogan, K., Rosenberg, J., & Denny, A. (2009)
Developed by the Climate Protection Partnership Division in the U.S. EPA, this is a great overarching handbook on Cool Roofs that we reference a lot. It clearly summarizes solar energy and reflectance, thermal emittance of materials, and different types of cool roofs and their benefits. Including this great table on energy savings from buildings that have converted to cool roofs.
Architecture 140: Energy and Environmental Management. UC Berkeley.
One of our professors shared this really comprehensive article on radiation with us. It details the following: Short and long wavelength radiation, The absorptivity, reflectivity, and transmissivity of translucent and opague objects, The emittance and absorptance of "whitebody" and "blackbody" materials.
Simulated Influence of Roof Reflectance on the Building Energy Balance in Two Northern Cities. Freund, S., Dettmers, D. J., & Reindl, D.T. (2006).
This experiment studies reflective roofs with different roof insulation and their effects on energy savings in Minneapolis. There are several experiments on the effects of white roofs in warmer climate areas, like Florida. This study is one of the few that examines the net energy savings in a more northern climate. The conclusion proved that even in cooler climates there is a net energy savings despite the slight increase in heating with a white roof. The results also showed savings potential depending on insulation levels.
More articles on roofing, urbanization, pollution, and hydrology coming soon!