Payback of PV solar

A question about : Payback of PV solar

Hi All,
please, I need to calculate payback of PV panel for three houses for one year .
Dimension of panel 3 * 4 .
Please, help me to calculate payback of panel .

Best answers:

• Got to concur with F&N, you're going to have to be a lot more forthcoming with your information because what you've given is very scant to say the least
  Another to add to the list:
  Cost of install/s?
• Hi,
  It would also be helpful to know the residential status of the 3 houses. Your main residence is straightforward but there could be tax implications if houses 2 & 3 were let.