As has been emphasised again and again, only a small fraction (5-10%) of energy put in is converted into usable form. In order to be prudent with the use of environmental resources, it is essential to increase the usable output while maintaining the same quantum of input i.e. - to increase efficiencies of end use devices, to reduce losses in transport and to minimise the number of stages of energy conversion. These are known as energy conservation methods, a few of them are discussed below.