Solar Water Heater
Solar Water Heaters/Geysers are chosen to provide hot water while harnessing nature's unlimited supply of Sun's Energy.
Normally all the solar water heaters are equipped with electrical backup which remains switched on through the day. So what really happens is that once the entire stock of hot water is depleted during morning hours, the electrical backup gets activated in order to heat up the water. So by the time when solar radiation starts picking up, this electrical backup in itself would have heated up the entire content of hot water.