Calculator
Solar Payback Calculator
Estimate system size, net cost after the federal credit, and how long solar takes to pay for itself.
Verified August 2026
Payback period
9.1 years
- System size
- 10.9 kW
- Gross cost
- $31,513
- Net cost after credit
- $22,059
- Estimated 25-year savingsAssumes modest utility rate escalation
- $47,769
- Annual production
- 16,500 kWh
Estimates only. Local pricing, site conditions and code requirements change the real number.
The formula
System kW = annual kWh / (sun hours x 365 x 0.8); Payback = net cost / annual savings
Florida averages about 5.2 peak sun hours per day. A 0.8 derate accounts for inverter losses, temperature and soiling.
Worked example
A $220 monthly bill at $0.16/kWh implies 16,500 kWh a year — roughly a 10.9 kW system, about $19,000 net after the federal credit, paying back in about 7 years.
Frequently asked questions
How long does solar take to pay for itself in Florida?
Typical Florida payback is 7 to 11 years at current rates, depending on your utility rate, roof orientation and whether you finance the system.
Do I need a new roof before solar?
If the roof has under 10 years of life left, replace it first. Removing and reinstalling panels later usually costs $3,000-$7,000.
Sources
Sources & verification
Last verified August 2026. Cost figures are modeled estimates based on national baselines adjusted for local labor and material pricing — they are not quotes. Permit rules change; confirm with the building department before starting work.