Like riding a bicycle instead of a SUV? No but I don't like things wasted and.. the water supply in Silab where I live is cheap but miserable. I'm not sure that I save with my system but know that I have water when needed even during a Brooooown Uooooot.
Any water tank painted black (55 gallon plastic drum if you want simple and relatively cheap) and left out in the sun here will get very hot in a matter of time. Another option is to lay out a stretched out coil of black polyethelene tubing on your roof. It will also get the water hot in relatively short order. Either can be plumbed to the hot water side of a shower faucet.
back in the old days (early 70's) : i made an outdoor solar hot water heater by laying 600 ft of ¾ '' black poly pipe on the ground. the water flowed by convection into an elevated recycled 30 gal hot water tank above the shower platform. just open the valve at the bottom of the tank to shower. not so great on cloudy days but worked great on sunny days. some days, the water needed to be cooled down with a mixing valve. larry H. pm me your eddress and i'll send you some fotos of our system. norm : ))~