Solar PV (photovoltaic) systems generate electricity when sunlight falls on solar panels which are normally made of crystalline silicon and mounted on the roof of the home or other building. Although a great deal of energy is consumed in the manufacture of PV systems, one installed they should continue to produce virtually free electricity for up to 20 years. - Description added by: www.microchap.info

Buildings are where the majority people in modern societies spend most of their time, whether in homes, commercial buildings, industrial facilities or retail complexes. The design and construction of buildings require a large investment of time, money and other resources. Then they require additional resources for running costs and maintenance. Bad design can greatly increase energy consumption over the whole lifetime of the building. Fortunately, good building design can greatly reduce energy consumption during construction and ongoing throughout a building's life. - Description added by: David Lockie