Guess it all depends on what you want from your system?
I’m not interested in ROI or how much I spent or saved. I’m more interested in convenience - as in no load shedding crap / no hassles with geyser timers or how many people can shower before hot water runs out or “oh shit” no hot water etc.
I also hate escum like all other corrupt anc run crap - so I don’t want to use pay them for heating my water - I’ve got the hottest thing in our galaxy to do that for me. My setup is a decent solar geyser + decent gas geyser.
I pump my solar geyser water through a temperature bypass valve, so depending on the season, hot water from SG goes straight to the house (summer) or from SG via the GG (winter) to the house, so I get better gas “mileage” because I’m not heating frigid ground water up to 60 degrees, but rather warm 35 - 40 degree SG water to 60 degrees.
This gives me 3 hot water options:
- SG direct to house = tempered to 60 degrees (summer)
- GG direct to house = tempered to 60 degrees (anytime)
- SG + GG mix - direct to house = tempered to 60 degrees (winter)
the benefit or rather convenience for me is hot water 24/7 x 365 days a years regardless of load shedding or seasons.