FREQUENTLY ASKED QUESTIONS – SOLAR GEYSERS

A Solar Water Heating system uses the sun’s energy to heat household water in place of the conventional electric geyser.
Water heated by the sun can reach temperatures exceeding 100 ºC if sized or installed correctly. The normal temperature for household use is 55ºC to 65ºC.
Solar Water Heating Systems are basically divided into two kinds of systems: direct or indirect.

A direct system is when the water to be heated is circulated directly through the solar collectors.

An indirect system is when the water is heated indirectly.  This is done by circulating an anti-freeze heating fluid through the solar collectors which is heated and then the heat from the fluid is transfer to the water through one method or another.  In areas where frost can occur, an indirect solar water heating system must be installed so as to prevent freezing of the solar collector.

Solar Water Heating Systems direct or indirect can be divided into two kinds of configurations: thermo syphon or pumped.

In a thermosyphon configuration the the SWH cylinder is located above the solar collector hereby allowing unassisted or natural circulation. No mechanical parts are present in this circulation method.

Pump systems utilize a pump to achieve circulation. In these systems the SWH cylinder is located below the solar collector therefore requiring assistance in circulation.

Yes and No. If the Solar Water Heating system is sized and installed correctly it can cater for all your family’s hot water needs with minimal lifestyle changes.  A boosting element such as an electrical element with a timer should be installed to cater for period’s when additional heating is required.
Yes.  Your existing electrical geyser can be used however it is only recommended as a pre-feed system.  Using the electrical geyser as the main SWH storage cylinder can be used but not recommended (see Using your existing geyser)
Generally all Solar Water heating systems come standard with an electrical back-up element which ensures that you have hot water even during overcast/rainy days and during the winter periods.  However the back-up element should be used in conjunction with a timer
To maximise the solar contribution during sunshine hours whilst still ensuring hot water during inclement weather a timer should be fitted.  The timer will allow for the backup electrical supply to the Solar Water Heating System cylinder to be isolated during the sunshine hours.
Yes. A Solar Water Heating system would require minimal maintenance to maintain optimal energy efficiencies. On average the maintenance periods can vary between 12 and 18 months but will also be dependent on the type of system or configuration installed, the water conditions and the type of solar collector/panels install. The supplier/manufacturer guidelines on maintenance should be considered before purchasing a Solar Water Heating system.
The cost may vary from R8 000.00 to R30 000.00 however it depends largely upon the following variables:

  • Size of the family to be served (and therefore the amount of heat required)
  • Size, type and brand of solar system
  • Type of roof upon which the panels are mounted
  • Orientation of panels
It depends upon the size of the system and the needs of your family and your current hot water usage.  The cost for water heating in a residential household is estimated at about 40% of a household’s entire electrical bill.  In an average household a person uses about fifty litres of hot water a day so a family of four could be spending about R520* just for heating water per month.

A correctly size and installed SWH system can reduce your hot water heating costs from between 40% to 75% which amounts to R210* to R390* per month (see Solar Savings Calculator)

(* calculated with a cost of KWH of R1.20)

Yes. The current Eskom rebate is available which can vary anything between R4000 and R10 000 depending on the type of SWH system installed.  Terms and Conditions apply to qualify for the rebate.
Solar Water Heating System does have a payback, and it can vary from three to ten years. But it may be more useful to think of SWH System as an investment that yields an annual return, much as a bank savings account provides interest. A solar water heater will generate savings that can equal a bank account generating between a ten (10%) and twenty percent (20%) annual return, and the savings are not taxed as income, as is the interest you earn at the bank.

The truth is, if you want hot water… you will be paying for that heat. You may prefer to pay your electrical bill forever, or you may wish instead to go solar, and become generator of your water heating.  Solar Water Heating is simply the best investment available today because it guarantees a return on money that you will otherwise “burn” and helps you develop equity as you bank your savings.