Gutty

Hi
Please excuse my terminology as I'm am not in the industry. 
I am paying close to R2000 a month on electricity in winter and R1500 in summer.
Currently I have  a 150l Kwikhot geyser + Geyserwise + Flat plate collector/solar panel.
I am staying in a 3-bedroom house, just me and the wife but the might be a baby on the way soon and I am also looking at building or buying a bigger place where my parents can come and stay with us, two or three years from now.  Not sure if it will be in the house or in a garden flat yet.  We both take a 5 to 8 minute shower in the evening and a slightly shorter one in the morning to wake us up before the caffeine has fully kicked in. 
I've done some minor research and it appears to me that a gas geyser might be the best option for heating water especially with current electricity tariffs. I'm paying between R2.72/kWh and R3.14/kWh at the moment in my area depending on monthly consumption.
Has anyone done a ROI or savings calculation on the below to options assuming it is a newbuild and everything would have to done from scratch or is there any existing posts or articles on this that anyone can recommend. I am also considering installing gas geyser on current house for nest 2 to 3 years if the ROI justifies it.
Electric Geyser VS
Gas Geyser VS
Electric Geyser + Gesyerwise + Flat plate collector VS 
Gas Geyser + Flat plate Collector, where the gas only needs heats up the shortfall to +-50 deg C
Thanks

Hi
Please excuse my terminology as I'm am not in the industry. 
I am paying close to R2000 a month on electricity in winter and R1500 in summer.
Currently I have  a 150l Kwikhot geyser + Geyserwise + Flat plate collector/solar panel.
I am staying in a 3-bedroom house, just me and the wife but the might be a baby on the way soon and I am also looking at building or buying a bigger place where my parents can come and stay with us, two or three years from now.  Not sure if it will be in the house or in a garden flat yet.  We both take a 5 to 8 minute shower in the evening and a slightly shorter one in the morning to wake us up before the caffeine has fully kicked in. 
I've done some minor research and it appears to me that a gas geyser might be the best option for heating water especially with current electricity tariffs. I'm paying between R2.72/kWh and R3.14/kWh at the moment in my area depending on monthly consumption.
Has anyone done a ROI or savings calculation on the below to options assuming it is a newbuild and everything would have to done from scratch or is there any existing posts or articles on this that anyone can recommend. I am also considering installing gas geyser on current house for nest 2 to 3 years if the ROI justifies it.
Electric Geyser VS
Gas Geyser VS
Electric Geyser + Gesyerwise + Flat plate collector VS 
Gas Geyser + Flat plate Collector, where the gas only needs heats up the shortfall to +-50 deg C
Thanks