I would like to mess with solar myself. I’ve had an idea or two cooking about some simple to build one off installations for water heater here at home.
We purchased an older home with a hot water system that was installed in 1983. It works perfectly, no maintenance, and free hot water all year, plus some domestic heating as needed. It makes a great deal of economic and engineering sense. Full disclosure - it’s sunny 300 days/year where we live. Send mail if you want more detail.
My parents have had a passive solar system since ‘82. My dad is convinced that they never recovered the cost even though there was a huge subsidy in ‘82 when it was built.
I am skeptical that it didn’t. Thirty years of providing hot water approx 5 mos out of the year. 5 x 30 = 150 mos @ $50 per month = $7500. Not bad.
It was still running last year running and providing hot water in the summer months and mostly in the Spring and Fall. It never provided heat to the house even though the builders promised that it would.
My dad said that it used some low maintenance liquid and that was why it lasted so long.
Oh, he did have to pay for some repairs a couple of years ago ~$600.
We live in Colorado and get a lot of sun.