The cold water supply is connected to the solar storage tank in your home. Water to be heated circulates between the storage tank and the solar collectors. The output from the solar storage tank becomes the cold water connection to the conventional gas, electric or oil water heater.

When a hot tap is opened, pre-heated water is drawn from storage into the conventional ("auxiliary") water heater. The burner or electric element turns on only if the temperature cannot be maintained by the solar heater. Most properly-designed solar water heaters will supply 50 to 70 percent or more of all the energy needed for water heating.