What is solar water heating?

Traditionally, conventional water heaters have been used to heat water for the home.  Powered by electricity, natural gas, oil or propane, these devices rely on energy that is nonrenewable and can be costly to produce and purchase.  Solar water heating, on the other hand, is a simple, clean and economical way to satisfy most of a family's hot water needs.
 
A solar water heating system has three main steps.  First, sunlight is captured by solar collectors outside, heating liquid inside the collector.  Second, heat from the liquid is transferred into hot water.  Third, the heated water is stored in an insulated tank until you need it.
 
Solar collectors are the largest component of a solar water heating system.  Most homes require one to three collectors.  Modern solar collectors are attractively finished and look similar to low-profile skylights.  For optimal performance, collectors should be on an unshaded, south-facing roof or wall that receives sunlight at least 80 percent of the time between 9 a.m. and 3 p.m. during winter and summer.