Solar Payback Calculator
Estimate how long it takes for solar to pay for itself based on your bill, financing choice, and whether you add a battery. California numbers, 2026 pricing, no email gate.
How this calculator works
Solar payback is the point where your cumulative utility bill savings equal what you paid for the system. After that point, every kilowatt-hour your panels produce is free electricity for the remaining life of the system. The math is straightforward in concept but depends heavily on five things:
1. Your monthly bill
Higher bills mean larger annual savings, which shortens the payback period. A $400/month bill in California typically pays back faster than a $200/month bill on the same system, because solar offsets more expensive grid power.
2. Your financing choice
Cash purchase gives the shortest payback because you avoid interest and dealer fees. Solar loans add a 15-30% dealer fee onto the system cost, which extends payback. Prepaid leases are competitive because the lease company can still claim the commercial 48E credit through 2027 and pass that value through.
3. Whether you add a battery
Under NEM 3.0, California pays exported solar at roughly 5-8 cents per kWh while you import evening power at 40-55 cents. A battery stores midday solar for evening self-consumption, which captures the difference. Without a battery, solar-only systems lose most of their economic edge under NEM 3.0.
4. Utility rate escalation
California utility rates have risen about 4-6% per year on average for the last decade. Higher escalation makes future solar savings worth more, shortening payback. The calculator assumes 4% annually.
5. Your specific roof and installer
System size, equipment selection, and installer pricing all vary. The number above is an estimate. The only way to know your real payback is to compare 2-3 quotes from vetted installers on the same project specs.
Frequently asked questions
How accurate is this calculator?
It uses California-average pricing and production numbers, which means the estimate will be within ~20% of your real payback for most homes in the state. For a precise number specific to your roof, utility, and installer pricing, compare real quotes through Solar Connect.
Does it include the federal tax credit?
No. The 30% federal Residential Clean Energy Credit expired December 31, 2025 and is not available for new installs in 2026. The calculator reflects post-credit economics. The commercial 48E credit still flows through prepaid leases through 2027, which is why prepaid lease pricing comes in lower per watt.
Why is the battery option checked by default?
Because in California under NEM 3.0, solar-only systems make significantly less financial sense than they did under NEM 2.0. Most California homeowners going solar in 2026 add a battery; the calculator reflects that default reality. Uncheck it to see the solar-only number.
What about SGIP rebates?
This calculator does NOT factor in SGIP rebates. Your real payback with a battery will be faster than shown — General Market tier saves you ~$2,400, Equity tier ~$11,000, Equity Resiliency tier ~$13,000+ on a 13.5 kWh battery. Tier eligibility depends on your utility, income, and location. Read our SGIP 2026 guide for the full breakdown.
How is "25-year net savings" calculated?
Year-by-year utility bill savings (escalating 4% annually), summed over 25 years, minus the upfront cost of the system. For loan financing, the system cost includes the dealer fee but not interest. For prepaid lease, the system cost is the lease payment.