Week3 pre-session reflection: Are Cool Roofs Green? The Answer’s Not Black and White.

Cool roof seems to be green, however, because of building type and other details, some zones' roofs are not as beneficial as it expected and some doesn't work in energy reductions. This essay talks about the factors which make cool roofs work. Researchers find that reflective roofs is good at cooling air temperatures and cool roofs are used to reduce urban island effect. Some cities agree, but some not. In some cities, the temperature would remain or even increase due to increased surface temperature, but this could be ignored because global temperature would decrease in a long term.

some factors may affect cool roofs. Snow is one of them, depending on its thickness and density, it may add to overall 'R-value' of the roof. Second one is solar radiation and glare because roofs would reflect radiation which may be absorbed by building. Also, reflective facades can reduce surface temperature.

 Therefore, from this article we can see that different design could make a big difference. Using cool roof in a good way can really reduce energy consumption, but how to design needs to be considered.