We bought a house with solar power and we are trying to get on the Iberdrola grid because it is a bit of a pain when the weather isn´t so good (as at the moment). I believe that the previous owners spent somewhere in the region of 25,000€ to install the system, which included 12 large batteries, approximately 6-8 years ago. We have had to replace the batteries at a cost of around 3000€ as the shed they are stored in has insufficient ventilation and they deteriorated much quicker than anticipated (apparently the life of the batteries is 10 years). So if you take that into account and spent 25000€, it would probably be the value of at least 20 years´ electricity. Therefore, I wouldn´t recommend it.

Hi Ian,
Solar heating is difficult because so much hot water has to be stored for use at night.
I run a combination of solar / and wood burner with back boiler
solar for the day and back boiler at night.

The hot water is circulated though underfloor heating, which is a concrete floor slab, with plastic water pipes in with insulation below

It gives a good back ground heat and the floor slab acts as a storage radiator.

But if you are not doing it in on a new build or major reform its not normally practical to install.

Cheers Tony