Q:

Do I still need a conventional gas/electric/oil water heater?

A:

If you want / need a consistant supply of hot water, yes. Solar water heating systems are normally installed as pre-heaters, preheating the cold water that supplies a conventional water heater. The energy savings provided by the solar system depends upon how close the temperature of the cold water is raised to the hot water heater's delivery temperature.

In seasonal water heating applications, or where the delivery temperature of hot water does not have to be consistant (for example at a cottage), a solar water heating system can have a ¨solar only¨ configuration. In this configuration, when the solar system runs out of hot water, there is no more hot water until the sun comes out again.