- Purchase (cash): Customer owns the PV system from day one, pays upfront with cash
- Purchase (loan): Customer owns the PV sysytem starting Day 1. It is purchased with a loan, sometimes with a down-payment and paid back at a fixed interest rate
- Lease, 15-year buyout: Install company or developer owns the PV System. Customer pays a fixed monthly payment that is adjusted for inflation. At 15 years, the customer elects to purchase the system and assumes full ownership.
- Lease, extension: Same as “Lease, 15-year buyout” except that in Year 15 the customer elects to extend the lease with the leasing company
We assumed a $4 cost per watt, along with the 30% federal ITC. Note that utility data is based on residential rates from EIA-861 forms, so some electric utilities’ rates might be out of date. Also note that insolation rates by zip code were gleaned from U.S. National Renewable Energy Laboratory data.
Solar calculator and all quoted content above via https://ilsr.org/simplified-solar-calculator/.