I live in S.A, I have RSM tank, Hailea 250 chiller, external cannister, lights 10 hours a day, chiller runs a lot due to S.A being a hot country.
I offset my tanks elec usage by fitting a geyser timer to my geyser, so now it runs 6 hours a day instead of 24/7, Iv found that even though the elec has recently gone up by 25% here Iv managed to keep my bill exactly the same @ +- R1000 a month