How much could I POTENTIALLY save?

Insert your average monthly electricity spend and Green Power's payback calculator will calculate your return of investment, in terms of annual electricity increases, water heating costs, the percentage of electricity bill used to heat water, and your cumulative and total saving through your use of a solar water heating system.

*Assume annual electricity increase:
Year 1 – 30%
Year 2 – 20%
Year 3 – 15%
Year 4 – 10%
Year 5 – 10%

# The electrical geyser uses 30 - 50% percent of your household's monthly electricity bill. Replacing your conventional
geyser with a solar powered system will reduce that percentage of your electricity consumption by up to 70 percent.

Source: http://www.eskomdsm.co.za/?q=Solar_water_heating_FAQs#replacing