A Cool Roof involves coating a roof with material that has higher solar reflectance (albedo) and thermal emittance (ability to radiate heat away from itself). Cool Roofs are perhaps less popular than green roofs because they do not offer amenities. However, in some situations they are more practical. In the short term, they are a much more cost effective solution. They can be easily installed as a retrofit to existing buildings since all they require is a currently intact and stable roof. No load bearing support work is needed prior to installation. They do have in common some benefits of a green roof, such as reducing energy cost, extending the life of the roof, and reducing the urban heat island effect.