A commonly-asked question is: “What kind of solar system is best for supplying domestic hot water? One with thermal solar panels, which heat the water directly? Or one using photovoltaic panels, which generate electricity to power a heating system?”

To consider this, the following comparison is useful - If a standard 3kw electric immersion heater takes around 5 hours to heat a 130-litre water tank from 10°C to 60°C then a THERMAL solar system needs two panels to achieve the same, requiring 4m² roof space and logically a PHOTOVOLTAIC system needs around twelve 230W PV panels (2.76 peak output) to achieve the same, requiring around 24m² roof space.

Therefore, for water heating, a thermal solar system is the only realistic option – much simpler, smaller and cheaper; plus being far more efficient and a faster return-on-investment.

However, photovoltaic systems are still an excellent investment for other domestic electricity needs.