Return on Investment of Solar Panels: How many times over?

[aoEAF2FBvC0MIo2Q 3,673]

OK, so hypothetically speaking, you are considering putting solar panels up on your roof and you're wondering if it's going to be worth it. In addition, solar panels are stated to last about 25 years (at least that's the local warranty). So then within those 25 years, those solar panels are going to be pumping electricity into your house as well as the electric grid and you'll be paid for all the energy that those panels generate.

 

Now, within that 25 years, how many times over does the investment have to pay for itself for you to think that the investment is worth it?

 

IMO that number is 3 times over:

1st time to pay for itself.

2nd time to pay for its eventual replacement

3rd to profit.

 

So that means that the solar panels installation would need to pay for itself once every eight years roughly for me to deem it to be a good enough investment. 

 

How many times over would it need to pay for itself, you think? It'd appreciated if you can give your reasoning as well.

[Draxon 214]

I would say that I would be content if I could just make up the initial investment in that time, because over that period of time, the technology would only get better, leading to more efficient, less expensive models being available by the time the first set expired.  Plus, being less dependent on electricity generated at a power plant is rewarding in itself.