Editing Solar energy (section)

==Architecture and urban planning==
{{Main|Passive solar building design|Urban heat island}}
[[File:Technische Universität Darmstadt - Solar Decathlon 2007.jpg|thumb|[[Darmstadt University of Technology]], Germany, won the 2007 [[Solar Decathlon]] in Washington, DC with this [[passive house]] designed for humid and hot subtropical climate.<ref>{{cite web|title=Darmstadt University of Technology solar decathlon home design |publisher=Darmstadt University of Technology |url=http://www.solardecathlon.de/index.php/our-house/the-design |access-date=25 April 2008 |archive-url=https://web.archive.org/web/20071018035727/http://www.solardecathlon.de/index.php/our-house/the-design |archive-date=18 October 2007 |url-status=dead }}</ref>]]

Sunlight has influenced building design since the beginning of architectural history.<ref name= "Schittich 2003">Schittich (2003), p. 14</ref> Advanced solar architecture and urban planning methods were first employed by the [[ancient Greece|Greeks]] and [[Feng shui#Archaeology|Chinese]], who oriented their buildings toward the south to provide light and warmth.<ref>Butti and Perlin (1981), pp. 4, 159</ref>

The common features of [[passive solar]] architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and [[Thermal mass (Building)|thermal mass]].<ref name= "Schittich 2003"/> When these features are tailored to the local climate and environment, they can produce well-lit spaces that stay in a comfortable temperature range. [[Socrates]]' Megaron House is a classic example of passive solar design.<ref name="Schittich 2003"/> The most recent approaches to solar design use computer modeling tying together [[Daylighting (architecture)|solar lighting]], [[solar heating|heating]] and [[solar air conditioning|ventilation]] systems in an integrated [[solar design]] package.<ref>Balcomb (1992)</ref> Active solar equipment such as pumps, fans, and switchable windows can complement passive design and improve system performance.

Urban heat islands (UHI) are metropolitan areas with higher temperatures than that of the surrounding environment. The higher temperatures result from increased absorption of solar energy by urban materials such as asphalt and concrete, which have lower [[albedo]]s and higher [[heat capacity|heat capacities]] than those in the natural environment. A straightforward method of counteracting the UHI effect is to paint buildings and roads white and to plant trees in the area. Using these methods, a hypothetical "cool communities" program in Los Angeles has projected that urban temperatures could be reduced by approximately 3&nbsp;°C at an estimated cost of US$1&nbsp; billion, giving estimated total annual benefits of US$530&nbsp; million from reduced air-conditioning costs and healthcare savings.<ref>{{cite web|author=Rosenfeld, Arthur |display-authors=etal |title=Painting the Town White – and Green |publisher=Heat Island Group |url=http://eetd.lbl.gov/HeatIsland/PUBS/PAINTING/ |access-date=29 September 2007 |archive-url=https://web.archive.org/web/20070714173907/http://eetd.lbl.gov/HeatIsland/PUBS/PAINTING/ |archive-date=14 July 2007 |url-status=dead }}</ref>