With now paying R0.9331 per kWh would it not be cheaper to install a lp gas geyser

I give up... what is a "gas geyser"?

Probably gas dryer. That's what I see in my xtal ball.

Water heater


1 watt = 3.412141633 BTU/Hr
1 BTU/Hr = 0.29307107 watts
1 Therm = 100,000 BTU

Have to know how you are buying gas, by the therm or by the cubic foot. If by cubic foot, need to know therms per cubic foot. Convert therms to BTU and calculate cost per BTU if gas.
Divide cost per watt by 3.412141633 to get cost of electric BTU.

Lp gas is sold by the gallon... BTU value is between 91330 and 91600.. depending on who you ask. (The government or the propane industry)