If your roof is correctly oriented and configured, then you will likely be able to save substantially with solar. General guidelines say a payback of 6-8 years if you purchase and at least 25% savings on your average bill if you lease.
Purchase for the greatest savings.
If you choose to purchase a solar system, after it pays for itself and assuming your usage stays the same, you can enjoy free electricity for 30 years or more, as SunPower panels have an expected life of 40 years.
Lease a system with free installation.
When you choose to lease a system, your savings begin right away! Take advantage of free installation and payments that are substantially less than your current electric bill.
Save on Federal Tax Credit.
If you purchase a system, you will be able to take 30% of the cost of the system as a tax credit, and can spread this credit up to five years if necessary. If you lease, the leaseholder will take the tax credit, but it will be reflected in lower payments for you.