Well if your roof is at the south you have no trees, 60% good weather and clean the panels each month you can get a real good return on investment over 15 years.
Most roofs are not to the south, there are lots of trees, there are lots of clouds, rain even in summer. Two years ago we had a hail storm causing 500M€ damage to roofs, glass, solar panels and cars. Lot of people were not insured, they had a storm clause but that excludes hail.
The sun shines in daytime while everyone is out working so the energy needs storage which is still very expensive.
So you need a converter per panel (lifetime 10 years) so if some shades comes on one panel not the entire array suffers, you need batterystorage (lifetime <10 years) or payback from the energy company for return of energy which in our country is being nihilated over the coming years. Yes that is right, you get €0 for the energy you give back because it is to popular and the energy companies can not handle the overload of generated energy, so they actually see it as a burden and want you to buy and expensive battery where they want to be able to drain energy from if needed, but you have to pay for it.
So hmmmmmm it is not that interesting IMO.
What is interesting though but restricted and also expensive is to warm water in the summer pump it 200m down in the ground and pump it up in the winter.
However you can not reserve your own tank at 200m down so how that works
?
So since my roof is to the west , I have trees and live in one of the cloudiest countries I will never go into solar my self.