[nw_arizona_granny]

But you can't eat the solar panels.

Yes they work, an Uncle in San Diego, had one of the first ones, he used it to heat hot water for the showers in about 4 apartments.

Worked, until the relatives showed up, for a week.

He used it for years.

Today's are not even related to his.

[Myrddin]

I put a thermo-siphonic solar hot water system into my home in San Diego. It had a 20 year "warranty". About 18 years longer than the manufacturer survived. The 80 gallon storage tank on the roof combined with the mixing valve provided all the hot water a family of 5 could use from mid-March until mid-November. The system was operated in "pre-heat" mode from November to March. The warmed water from the storage tanks passed through the gas hot water heater for a final boost in temperature.

The cost of gas never rose high enough to result in amortizing the cost of the system...even after a fairly significant tax credit. The hard water in San Diego destroyed the storage tank and pressure relief valves. In time, the insulation in the storage tanks became wet and the insulation failed to do the job. The tanks were discarded when I put a new roof on the house. I found a contractor in San Diego who still had a few customers with systems that used those panels. He took them off my hands. Overall, I probably lost $10,000 on the whole experience. Never again.