The difference between solar hot water and solar photovoltaic or solar panel systems is one of our most commonly asked questions.
Both harness the sun’s energy but that is where the difference ends.
A solar hot water system uses the sun’s thermal energy trapped in a hot box collector to transfer thermal energy to heat up the water in your hot water cylinder.
A solar panel or solar PV system captures photons or particles of light to know electrons free from atoms generating electric flow or current.
Solar hot water systems are relatively inexpensive and can be used to provide abundant hot water to your home during the temperate time of the year. Their disadvantage is that they can only provide energy to your geyser and not your home’s other appliances and are ineffective in winter requiring and electrical backup system to be in place.
A simple way to know if your solar thermal system is working or effective is if when you enter your car after it being parked in the sun and it is uncomfortably hot then during this time of the year your solar hot water system is effectively heating your water. If when you enter your car the temperature inside your is moderate then a solar hot water system will be ineffective at heating the water in your geyser.
Solar PV or solar panel systems provide power to all the appliances in your home including your geyser and don’t need the weather to be hot or thermal energy to create energy even in winter only sunlight or photons are needed to generate electricity.
Their disadvantage is that they have a much higher cost.
A newer and very efficient innovation is the introduction of DC or direct current elements that can be retrofitted to existing geysers using solar PV (Photovoltaic) panels to heat your water without the need for an inverter.