Heating water with solar PV: dedicated systems and surplus
Sources checked
PV can heat water through a dedicated panel-and-water-heater system or by directing surplus from a household PV installation into a suitable heating element. Choose from the existing tank, daily hot-water use and whether PV is already installed.
Two arrangements, different requirements
A dedicated PV water-heating system primarily serves the tank. A household surplus controller sends electricity not currently needed elsewhere to a compatible heater. Confirm the voltage, heating element, controller and safety controls for the exact arrangement.
A storage tank alone does not prove compatibility. Include the controls, wiring changes, installation and an alternative heat source for periods of inadequate solar production.
Size it around useful hot-water demand
Estimate daily water use, tank capacity and when reheating is needed. Summer surplus does not guarantee winter hot water, and a full hot tank cannot absorb unlimited surplus energy.
PV water heating is different from solar thermal collectors, which deliver heat through a fluid circuit. Compare complete costs, maintenance and the useful output of each system rather than counting panels or assuming one technology is always preferable.