since the days of Adam". After Palmer's patent expired in 1843, "corrugated galvanized iron" (CGI) became a world-wide favorite roofing material. In the later 19th century, steel mills replaced iron works, and the product using steel could be made thinner for the same span and stiffness performance, but the term "CGI" remains in the UK and Australia up to the present. In the early 20th century, after being used for military purposes in the trenches and for Nissen or Quonset huts, "CGI" roofs were widely used but had low status. After architects such as Walter Gropius and Buckminster Fuller used the material, and with shiny and streamlined "desert modernist" designs such as Pierre Koenig’s Stahl House (with an interior exposed metal roof, but not actual CGI), it recovered status. Albert Frey’s 1964 Palm Springs house used actual corrugated steel as roofing, as well as corrugated aluminum exterior siding. Environmentally friendly Metal roofs are 100% recyclable and can be made from other recycled products. Asphalt shingles are petroleum based with other chemicals making their recycling process more toxic, most shingles are not recycled and 20 billion pounds are sent to landfills every year and take hundreds of years to decompose. Metal roofs emissivity is better at reflecting solar radiation at 10%-75% depending on the color choice, compared to asphalt roofs that reflect 5%-25% depending on their color. Over the lifetime of the metal roof they keep 95% of the reflective capacity compared to other roof types that loose 20%-40% of their reflective capacity. The highly reflective coatings in the paint of metal roofing can lower utility bills by 40%. Advantages Metal roofs can last up to 100 years, with installers providing 50-year warranties. Because of their longevity, most metal roofs are less expensive than asphalt shingles in the long term. Metal roofing can consist of a high percentage of recycled material and is 100% recyclable. It does not get as hot as asphalt, a common roofing material, and it reflects heat away from the building underneath in summertime. On a larger scale, its use reduces the heat island effect of cities when compared to asphalt. Coupled with its better insulating abilities, metal roofs can offer not only a 40% reduction in energy costs in the summer, but also up to a 15% reduction in the energy costs in the winter according to a 2008 Study by Oak Ridge National Laboratory. This