Slightly off topic solar water not solar electric, yesterday we went to the Kilcoy Agricultural show, highlight of the rural social season, such a difference from city RAS shows, actually useful,
for hot water the difference between flat panel collectors and the evacuated tube kind cost is neglible
but the installer (who does both kinds) had their demo models,
flat panel one been up for an hour ~20degrees
evacuated tube, been up for an hour, flashing the water to steam, hot enough for coffee, and the evacuated tube ones dont lose heat overnight, there is no water in the tubes to radiate heat out
probably this is only news to me, but it is very impressive, the solar hot water panel on our house in kilcoy, is stinking cold for m orning showers