It is also a good point though that of course it won't be worth it if it just generates $10 a year or whatever. So that is indeed something to consider, especially as difficulty goes up and rewards are halved. I will have to carefully look at the hardware suggested here (S9 and S19 with some boards disabled) to see what makes sense for me.
It's also worth mentioning that the continuous OFFs and ONs are pretty bad and shorten the miner's lifespan considerably if done too often, miners LOVE to run at a steady state, so it's good if you want to give it a 1-day rest -- it probably won't mind that, but turning it off and on a dozen times a day is bad, to somehow mitigate this issue you would either buy a dirt cheap old gear like S9 or Avalon 7-8 series, so that replacing it won't break the bank, or, you get a very, very efficient gear which you can run on grid for cheap while making good enough income.
Yes indeed. That's why the plan is (if I'm going through with this project) to use low power like 500W, so that I would be able to basically run the miner throughout the day pretty much always, as there will be enough unused power to run it while it is daylight, more or less. And not to just turn it on for half an hour and then off again while the sun is shining maximally onto the panels.
Some people (including "experts") I talked to suggested not getting a thermal solar installation anymore, but just PV and simply doing that instead for hot water.
PV is more versatile that's for sure, it's also space efficient, but speaking of efficiency in heating water, thermal solar is at least 50% more efficient, it doesn't require a lot of knowledge to figure out the loss of sun > heat is a lot less than Sun > AC > DC > heat, unless they have a different reason which I am not aware of.
Yes definitely. Although with a heat pump that can apparently around 4x the energy input, the difference might disappear in a sense. And if I run a miner, it would be extra utility ("free" bitcoins) as well.