We’ve just moved into a house with solar thermal (hot water) but don’t know much about it.
Had a few chilly showers till we started boosting the heat with 30mins from the gas in the middle of the night (the previous owners said that the central heating system would only boost the hot water if it was dark - otherwise the solar panels try). I have watched the display show the water heating up through the day though - quite magical seeing us get hot water for nothing (as we didn’t have the cost of installing it).
Hoping to switch off the gas boost as we get longer days and sunnier weather…
The electricity solar panels may be cost effective at the moment as there is something called a feed in tariff where you get paid for all the electricity you produce - even the stuff you use yourself. Not sure how this works in practice though and it needs to be a registered installer to get this.